1. BALANUS TINTINNABULUM. Pl. 1, fig. a-l; Pl. 2, fig. 1 a-1 o.

LEPAS TINTINNABULUM. Linn. Syst. Naturæ, 1767.

 ——  ——  ——   —— Ellis. Phil. Transact., vol. 50, 1758, Tab. 34, figs. 8 and 9.

 

 ——  ——  ——   —— Chemnitz. Neues. Syst. Conch., 8 B. (1785), Tab. 97, figs. 828-831.

BALANUS TULIPA. Bruguière. Encyclop. Meth., 1789; sed non B. tulipa alba, in Chemnitz; neenon B. tulipa, O. F. Müller, Zoolog. Dan.; neenon B. tulipa, Poli, Test. ut. Siciliæ.

 ——   ——  — G. B. Sowerby. Genera of Recent and Fossil Shells, Tab. Genus Balanus.

LEPAS CRISPATA (var.) Schröter. Einleitung Conch. vol. iii, Tab. 9, fig. 21.

  —— SPINOSA (var.) Gmelin. Linn. Syst. Nat.

  —— TINTINNABULUM, SPINOSA, CRISPATA ET PORCATA. W. Wood. General Conchology, 1815, Pl. 6, figs. 1, 2. Pl. 7, figs. 4, 5. Pl. 8, figs. 1-5.

BALANUS TINTINNABULUM. Chenu. Illust. Conch.

  ——  — D’ORBIGNII (var.) Chenu. Illust. Conch., Tab. 6, fig. 10, sed non Tab. 4, fig. 13.

  ——  — CRASSUS (Foss.) Sowerby (!). Min. Conch., 1818. Tab. 84.

Chenu gives several admirable figures of this species; but he confounds some forms certainly distinct under this name, for instance the B. tulipiformis of this work.

Shell varying from pink to blackish purple, often striped and ribbed longitudinally: orifice generally entire, sometimes toothed. Scutum with the articular ridge broad and reflexed. Tergum with the basal margin generally forming a straight line on opposite sides of the spur.

Var. (1) communis (Pl. 1, figs. a, b, f supra; Pl. 2, figs. 1 a, 1 c, 1 d, 1 e, 1 i, 1 k): conical or tubulo-conical; smooth or moderately ribbed longitudinally; colours varying from purplish-pink to blackish-purple; often in obscure longitudinal stripes; orifice of shell rounded-trigonal.

Var. (2) vesiculosus (young) (Pl. 2, fig. 1 h): exterior surface of the scuta impressed with small square holes, arranged in two or more rows, radiating from the apex of the valve.

Var. (3) validus (Pl. 1, figs. c, f infra): globulo-convex; coarsely ribbed, ribs flexuous; either smooth or rugged; pale chocolate purple or pink; shell extremely strong; orifice almost circular.

Var. (4) zebra (Pl. 1, fig. g): conical; rich chocolate purple with broad snow-white ribs; sheath bright chesnut colour; summits of alæ oblique; orifice almost circular.

Var. (5) crispatus (Schröter) (Pl. 1, fig. h): pale blueish or pinkish-purple, with irregular rough projections, or with short, sharp, needle-like points; scuta with their exterior surface either plain, or with radiating lines formed of hood-like projecting points.

Var. (6) spinosus (Gmelin) (Pl. 1, fig. i): globulo-conical or cylindrical; shell rather thin, with long, upcurved, nearly cylindrical, very sharp points; colours very pale; attached to other specimens, and to Lepas anatifera.

Var. (7) coccopoma (Pl. 1, fig. d; Pl. 2, fig. 1 f, 1 l, 1 o): globulo-conical; orifice small, rounded; walls generally smooth, thick; intense rose-colour, sometimes most faintly striped longitudinally with varying shades of pink; radii tinged with purple; scutum sometimes as in var. communis, sometimes with its basi-tergal corner much cut off, with the adductor ridge prominent, the pit for the depressor muscle deep, and the articular ridge broad and hooked; tergum sometimes as in var. communis, sometimes with a broader spur, placed nearer to the basi-scutal corner of the valve.

Var. (8) concinnus (Pl. 1, fig. e; Pl. 2, fig. 1 g): globulo-conical; walls finely ribbed; dull purple, tinged and freckled with white; scutum, with a broad, hooked, articular ridge, with an extremely sharp plate-like adductor ridge, and with a cavity, bordered by a plate, for the rostral depressor muscle; tergum as in var. 1.

Var. (9) intermedius: radii with their summits slightly oblique; parietes pale blueish purple, with narrow dark purplish-blue longitudinal lines; sheath with the internal surface of the rostrum and lateral compartments much darker colored than the internal surface of the carina and carino-lateral compartments; scuta and terga as in var. communis.

Var. (10) occator (Pl. 1, fig. k; Pl. 2, 1 b): radii with their summits slightly oblique; parietes smooth, or ribbed, or spinose; very pale blueish-purple, with narrow darker longitudinal lines; sheath with the internal surface of the rostrum and lateral compartments dull blue, whilst the corresponding parts of the carina and carino-lateral compartments are white; scuta with small, sharp, hood-formed points, arranged in straight radiating lines; terga with the spur placed at either its own width, or less than its own width, from the basi-scutal angle.

Var. (11) d’Orbignii (Chenu) (Pl. 1, fig. l; Pl. 2, 1 m, 1 n): radii with their summits oblique, and the orifice of the shell rather deeply toothed; shell conical or tubulo-conical, smooth, or rugged; colour dull purplish-lilac, with the tips of the parietes and a band along one side of the radii quite white; sheath rather darker at the rostral than at the carinal end; scuta as in var. 1; terga as in var. occator.

Habitat. — West coast of Africa, on mytili; Madeira, on rocks; West Indies; Cape of Good Hope, on a patella and on kelp; mouth of the Indus; East Indian Archipelago; Sydney, Australia, attached to Lepas anserifera, adhering to a floating cane; Peru; Galapagos Islands; West Mexico; California. Extremely common on ships’ bottoms arriving from West Africa, India, and China, often associated with B. amphitrite.

Fossil Red Crag, England; Mus. S. Wood and J. de C. Sowerby. — Touraine (?); Mus. Lyell.

General Remarks. — This, the first species of Balanus, is, perhaps with the exception of B. amphitrite, the most difficult and variable in the genus. There are some other species which vary quite as much in external appearance; for instance, B. perforatus; but B. tintinnabulum also varies in far more important points, as in the proportions and structure of the opercular valves. The difficulty in determining whether or not the differences are specific, is wonderfully increased by whole groups of individuals varying in exactly the same manner. I have seen three most distinct varieties taken from the bottom of the same vessel, so that I did not at first entertain the least doubt that they were three distinct species. I may mention, as showing the vacillations which I have experienced on this subject, that beginning with the impression, that the above three varieties were really distinct species, after going over the several immense collections of specimens placed at my disposal, I came to the conclusion that the above three, and several other forms presently to be described, were only varieties; yet after an interval of some months, having to look at some of these specimens again, I could not but think that I had come to a false conclusion, and so went into all the details again, and satisfied myself that I had followed a right course; after another interval, I had to repeat the same process, and even now I can never look at a group of the beautifully coloured shells with their small rounded orifices of var. coccopoma attached to the Avicula margaritifera, or again at var. d’Orbignii, with its toothed orifice and white tips to the compartments, without thinking that they must be specifically distinct from the dull-coloured specimens with large entire orifices so common on ships’ bottoms; yet I can produce a full series of intermediate forms, and I can further show, in each variety, that the several points of difference by which each is characterised, are variable. I may be permitted to add, in order to show that it has not been from indolence that I have combined so many forms, that I had named and already written out full descriptions of most of the varieties, before determining to sacrifice them.

Seeing that B. tintinnabulum and amphitrite are the two most variable species in the genus, more especially in the important characters derived from the opercular valves, and knowing that these species are attached so very frequently to ships’ bottoms, one is led to suspect that their extreme tendency to vary may be due to their being exposed to varying and peculiar conditions, whilst transported to new and distant localities. It is even just possible, as may be inferred from the facts given in the Introduction () in regard to certain monstrous specimens of Bal. balanoides having been apparently impregnated by adjoining individuals, that the varieties may interbreed, and so produce numerous intermediate forms. Whether or not this could take place, I am inclined to look at these two species, as in an almost analogous condition with our domestic animals, which give rise to such infinitely numerous varieties. It appears to me probable, that several of the varieties keep true to their peculiarities, as long as they continue to breed in the same locality; but that when their larvæ become attached to ships’ bottoms, and are thus transported and exposed to new conditions, they give rise to new and ever-varying varieties. I will first give a full description of the more common forms of B. tintinnabulum, which undoubtedly belong to the same species, only alluding to the less frequent points of difference, and then separately describe the more marked varieties.

General Appearance. — Shape of shell generally tubulo-conical, or conical, or globulo-conical, rarely depressed. Orifice either large and rounded-trigonal, or small and oval, either entire or less frequently toothed. Surface quite smooth, or longitudinally ribbed; ribs of variable strength, not unfrequently flexuous or branching, sometimes roughened with blunt or sharp projecting, irregular points, or more rarely with almost cylindrical, upturned, long spines; the simple longitudinal ribs are generally most strongly marked in young specimens. Colour, generally varying from pink, to pink tinged with purple, to dark, inky purple, more or less striped, longitudinally, with white or pale tints; rarely the shell is of the brightest rose-colour, either uniform or longitudinally striped; sometimes it is pale purplish, or dark blue; and sometimes dark chocolate-purple: the ribs, when present, are generally more or less white, sometimes snow-white. That there is much variation in colour, and in the prominence of the longitudinal ribs, is quite certain, as the two sides of the same individual sometimes differ greatly in these respects. The radii are generally rather darker coloured than the parietes, but sometimes they are lighter, even in the darkest tinged specimens. The surfaces of the radii are occasionally finely plaited in lines parallel to the basis. In some infrequent varieties the radii have oblique summits, making the orifice of the shell to be toothed. The sheath is generally feebly coloured, but sometimes bright chesnut-brown, and sometimes blueish. The strength of the shell varies considerably; some of the globulo-conical varieties are extremely massive. Size; basal diameter of largest specimen very nearly three inches; height of the highest specimen three inches.

Young specimens are apt to have a peculiar aspect; for their shell is often strongly ribbed longitudinally, and the summits of their radii are sometimes oblique. Their scuta are sometimes deeply pitted in radiating lines. Their colours are generally pale. I have seen specimens attached to kelp from the Cape of Good Hope, with their parietes white and ribbed, and their radii mottled with pinkish-purple; I have seen other young specimens from the Galapagos Archipelago, of a uniform grayish-blue.

The Scuta generally have their lines of growth moderately prominent; occasionally they are longitudinally striated, with the lines of growth flexuous and upturned at intervals into small, sharp, hood-liked projections, which are symmetrically arranged in straight lines radiating from the apex of the valve; I have seen this structure in some specimens of var. crispatus and in var. occator (Pl. 2, fig. 1 b); and I have noticed an intermediate state in var. communis. The degree to which the basi-tergal corner of the valve is rounded off varies much even in var. communis (Pl. 2, fig. 1 a, 1 d, 1 e). The articular ridge (1 c, 1 e) is broad and much reflexed; and often, but not always, distinctly hooked (1 f). The adductor ridge is confluent with the articular ridge, and runs straight down the valve, bounding the cavity for the depressor muscle; generally the adductor ridge is blunt, and so little prominent as barely to deserve notice; but I have seen it sharp and prominent in one specimen of var. communis, and it is generally prominent in var. coccopoma (1 f), and most remarkably so in var. concinnus (1 g). The cavity for the lateral depressor muscle is generally very slight; but in the two vars. just mentioned, and sometimes in var. communis, it is deep. In var. concinnus (1 g) there is a remarkable plate developed for the attachment of the rostral depressor muscle. The scuta are coloured either dull-purple or reddish, or striped longitudinally white and blue. The surface is sometimes externally depressed in the line of the adductor ridge; and in young specimens there is sometimes, along this line, a chain of pits (1 h), as in full-grown specimens of B. trigonus and lævis.

The Tergum (Pl. 2, figs. 1 i to 1 o) is broad, with a generally closed longitudinal furrow; this furrow is open in young specimens, and it is often, but not always, open in rather large specimens of var. occator; it is always open in var. d’Orbignii (Pl. 2, fig. 1 m), and sometimes in var. concinnus. Apex barely beaked, except in var. spinosus, in which it is sensibly produced. Spur placed either very nearly in the middle of the basal margin, or when least medial, it stands at above its own width from the basi-scutal angle; yet in some specimens of var. occator the spur is less than its own width from this angle. The basal margin (1 i), on opposite sides of the spur, either forms a nearly straight line, or the scutal portion descends lower than the carinal portion, and curves very regularly towards the spur; this is the case in var. d’Orbignii (1 n), and in some specimens of var. occator. The carinal half of the basal margin generally forms an angle with the spur of only a little above a rectangle. The spur varies a little in length and breadth, but never exceeds one fourth of the greatest breadth of the valve. The scutal margin is broadly inflected, the inflected portion forming either a right angle, or somewhat less than a right angle, with the exterior surface of the valve. Internally the articular ridge is prominent, and is either considerably or slightly curved; it extends down either about half, or three fourths, of the length of the valve. The spur is produced for a considerable distance up the internal surface of the valve as a prominence. The crests for the tergal depressor muscle are very feeble. In one specimen, in which both the shell and operculum had undergone much disintegration, the scuta and terga were calcified together.

Compartments: their exterior appearance has been already described. The parietal tubes are not large; they are generally crossed by transverse septa in their uppermost part; but they are sometimes almost solidly filled up by dark shelly layers. The internal surface of the parietes is more or less plainly ribbed; in old specimens, however, it generally becomes smooth. The radii have their septa denticulated on both sides; and they are porose, that is, the interspaces between the septa are not filled up solidly. The radii generally extend from tip to tip of the adjoining compartments, that is, their summits are parallel to the basis; but in three not common varieties, viz., vars. intermedius, occator, and d’Orbignii (the former of which at least must, without the smallest doubt, be ranked as a mere variety), their summits are oblique. I have occasionally met with specimens of var. communis with oblique radii; and this is not very infrequent in young shells. Exteriorly the radii are generally smooth, but sometimes finely ribbed horizontally, owing to the projection of the septa. The alæ have their sutural edges smooth; their summits are usually parallel to the basis, but they are often much broken; in var. zebra, however, in every specimen which I examined, the summits were oblique. The sheath varies much in colour: in var. occator, and in a less degree in var. intermedius and var. d’Orbignii, the portion lining the rostrum and lateral compartments is much darker than the other parts of the sheath. The Basis generally has a thick, underlying, cancellated layer. Sometimes the basis (Pl. 1, fig. b) is irregularly cup-formed.

Mouth: labrum with four or six minute teeth: mandibles with five graduated teeth; inferior point more or less spinose. Maxillæ, either with or without a small notch, beneath the upper pair of spines; in the lower part there are two spines longer than those immediately above them. Cirri, the first pair has the rami unequal, in the proportion of about 19 segments in the longer ramus, to 16 in the shorter. The segments in the latter have their anterior surfaces very protuberant. The second pair is short, with the anterior surfaces of the segments protuberant. On the thorax (Pl. 25, fig. 1), on each side, at the bases of third pair of cirri, there is a projecting membranous plate fringed with fine bristles. The three posterior pairs have their segments shield-shaped in front, generally bearing four pairs of spines, of which the lower pair is minute; between these pairs there are some minute spines. In some young specimens from the Cape of Good Hope, and in var. concinnus, I found six pairs of spines on the segments of the posterior cirri.

Geographical Distribution. — This species is extremely common over the whole of the warmer seas. It ranges from the Island of Madeira to the Cape of Good Hope, and on the west coast of America, from Monterey, in lat. 37° N., in California, to Peru. It is attached to rocks and sub-littoral shells, to floating timber, to kelp, and to Lepas anatifera. It is attached in wonderful numbers to ships’ bottoms arriving at our ports, from West Africa, the West Indies, the East Indian Archipelago, and China. It is generally associated with B. amphitrite and amaryllis. I have already stated that, on the bottoms of vessels, the different varieties are generally grouped together; and this makes me believe that they are local. In Mr. Stutchbury’s collection there are numerous specimens taken from a ship which first went to the west coast of Africa for guano, and then to Patagonia for the same object, and it was interesting to see the manner in which numbers of B. psittacus, a Patagonian species, had become attached on the African B. tintinnabulum. The varieties from the west coast of America seem eminently peculiar; we there find var. coccopoma and concinnus; and a blueish, rugged variety, with peculiar opercular valves.

Geological History. — I have seen specimens in Mr. S. Wood’s collection from the Red Crag of England, which, though not accompanied by opercular valves, I cannot doubt belong to this species. The specimens named by Mr. Sowerby, in the ‘Mineral Conchology,’ as B. crassus, and which I have seen through the kindness of Mr. J. de C. Sowerby, also belong to this species. I further believe that a specimen in Sir C. Lyell’s collection, given to him by M. Dujardin under the name of B. fasciatus from Touraine, is likewise B. tintinnabulum.

Varieties.

With respect to var. communis, I have nothing to remark. The second, var. vesiculosus (Pl. 2, fig. 1 h), is confined to young specimens, and may, perhaps, be due to a want of calcareous matter. With respect to var. validus (Pl. 1, figs. 1 c, 1 f infra), I may observe that some of the coarsest and strongest specimens which I have seen were said to have been attached to a surface of iron. I have seen two large lots of var. zebra (1 g), taken by Mr. Stutchbury, from the bottoms of ships, arriving from Bengal and China, and in both cases associated with var. communis, and in one case with var. coccopoma. I at first thought that this variety, zebra, was specifically distinct, but now I feel no doubt, that it is a mere variety; its body was in every respect identical with that of var. communis.

Nor have I any doubt that var. crispatus, of Schröter (Pl. 1, fig. h), is only a variety, although the scuta in some specimens have a peculiar appearance, externally like these valves in var. occator (Pl. 2, fig.1 b): the scutum is here broader and flatter than in var. communis, and the adductor ridge is very feebly developed, but we shall see how variable this ridge is in all the varieties: externally, the sharp, hood-like points formed by the upturned lines of growth, have a very remarkable appearance, from being arranged in quite straight radiating lines. This structure is evidently caused by the same tendency which produces on the walls the sharp, upturned, irregular points; but it is singular that the scuta are smooth in some specimens with very rough parietes; and, on the other hand, bristling with the symmetrically arranged, hood-like projections, in other specimens on which I could with difficulty detect only a few exceedingly minute points on the walls. In var. communis I have seen a few specimens with a slight tendency in the scuta to become striated longitudinally. The tergum in var. crispatus presents no difference from that in var. communis. Some of the roughest and best characterised specimens of var. crispatus appear to have come off copper-sheathed vessels.

I believe var. spinosus of Gmelin (Pl. 1, fig. i), has been correctly considered by me as a variety, but I have unfortunately seen only one set of specimens with their opercular valves preserved: these were attached to Lepas anatifera. The colour of the shell varies from reddish-purple to nearly white; the radii are sometimes quite white; the walls are slightly ribbed. The scuta in the above specimens, externally were smooth; the adductor ridge was rather more distinct from the articular ridge than in any other variety; and the terga rather more plainly beaked. The tubular, up-curved, calcareous spines sometimes occur only on one side of the shell, and often only in the lower part. These spines are often coloured brighter than the walls. Their presence cannot be accounted for (any more than the state of the scuta in the foregoing var. crispatus) by the nature of the surface to which they are attached; for I have seen one set attached to a large rugged specimen of B. tintinnabulum, and another to the very smooth valves of Lepas anatifera. I believe that this form is almost always associated with var. communis, which is an argument that it is only a variety.

To var. coccopoma (Pl. 1, fig. d) I alluded in my introductory remarks as having so strongly the aspect of a distinct species. I possess a beautiful group, with a globulo-conical, smooth shell, of the finest rose colour, with a rather small, rounded orifice. These specimens were attached (mingled with B. trigonus) to Avicula margaritifera, from, as Mr. Cuming believes, Panama. I can never look at this set of specimens without doubting the correctness of the determination at which I have arrived. In the British Museum there are two sets of specimens taken off a vessel, on the west coast of South America, almost identical in external appearance with those in my possession, but rather more rugged. Mr. Stutchbury has sent me some specimens from a ship, direct from China, which are rather paler pink, and more striped, and come near to some ordinary varieties of B. tintinnabulum. The scuta (Pl. 2, fig. 1 f) in the above three sets of specimens agree in having the adductor ridge more developed, and the pit for the lateral depressor muscle deeper than is usual. The tergum (1 l, 1 o) in most, but not in all these specimens, has a rather broader spur; and some of the specimens have the carinal portion of the basal margin considerably hollowed out; the spur, also, is placed nearer the basi-scutal angle than in ordinary cases. On the other hand, in Mr. Cuming’s collection, there are two specimens taken off a vessel, identical in external appearance with the foregoing, but which have scuta and terga in every character exactly as in var. communis; hence I am compelled to consider all these specimens as mere varieties.

Var. concinnus (Pl. 1, fig. e) is, perhaps, the most remarkable of all the varieties; I have seen three sets of specimens from the west coast of South America, — all identical in appearance, having longitudinally-ribbed walls, either rosy or of a dull purple, striped and freckled in a peculiar manner with white. I have, however, seen an approach to this colouring in some few specimens of var. communis; and the shell itself offers no other peculiarities. The scutum (Pl. 2, fig. 1 g) resembles, in general shape, that of var. coccopoma; but the adductor ridge is here much sharper and more prominent; and the rostral depressor muscle, instead of being lodged in a little cavity formed by the folding over the occludent margin, has, in addition, a small plate on the under side, which tends to convert the pit into a tube. The tergum exactly resembles that of var. communis. The segments in the sixth cirrus bear six, instead of four, pairs of spines, — a circumstance which I have noticed only in some young specimens of var. communis, from the Cape of Good Hope. From these several peculiarities, until quite lately, I resolved to keep this form specifically distinct; but I have finally concluded that they are not sufficient. For firstly, I have seen a scutum in var. communis (Pl. 2, fig. 1 d), with the adductor ridge nearly as sharp; and this ridge is always strongly pronounced in var. coccopoma; secondly, with respect to the plate for the rostral depressor muscle, although I have not seen this in any other variety, yet in Bal. concavus a closely analogous plate, situated in the lateral depressor cavity, is highly variable, and I am not willing to found a new species on one minute point of structure, — a structure which is variable in another species of the same genus.

I have seen some cylindrical and conical specimens of B. tintinnabulum, from the coast of Mexico and California, only noticeable, as far as the shell was concerned, from being rugged, and of a dull blueish-purple; but which had opercular valves exactly like those of var. coccopoma, and therefore, as far as the scutum is concerned, approaching closely in structure to var. concinnus, — all three from the west coast of America. Hence I was at one time led to believe that there existed a species on this line of coast, which represented B. tintinnabulum, and which varied in external shape and colour in an analogous manner to that species. But as the opercular valves in var. coccopoma are sometimes identical with those of var. communis, and as this is always the case with the tergum of var. concinnus, and as the shell itself presents no differences, it is scarcely possible to admit the existence on the west coast of America of this supposed representative of B. tintinnabulum.

With respect to var. intermedius I have little to say in addition to the character given above: I have seen only two groups of specimens in Mr. Cuming’s collection: the chief interest in this variety is that it shows that the next form must be ranked as a variety, and not as a distinct species.

Of var. occator (Pl. 1, fig. k) I have seen several specimens, mostly taken off the bottoms of vessels, and one specimen, marked in Mr. Cuming’s collection “South Seas.” After having carefully examined these specimens, I came to the conclusion, that the slightly oblique radii — the general colouring, and more especially that of the sheath — the scuta (Pl. 2, fig. 1 b), with their sharp hood-like points, in radiating lines — and the terga, with the spur so near to the basi-scutal angle, were amply sufficient to distinguish it as a good species. Subsequently, however, I found that the scuta in var. crispatus presented, both externally and internally, exactly the same peculiar appearance. In var. intermedius, I found the summits of the radii equally oblique, and the general colouring nearly the same, and more especially a close approach to the singular circumstance of the sheath differing in colour towards the opposite ends of the shell. So that the position of the spur of the tergum was the chief remaining character; and this evidently varied considerably in the four or five specimens examined by me, being either its own width, or much less than its own width, from the basi-scutal angle: the outline, also, of the small portion of basal margin, between the spur and the basi-scutal angle, likewise varied much, being either angularly indented, or gradually curved down towards the spur: so also the tip of the spur varied in shape. The longitudinal furrow is unusually apt, in this variety, to remain open. We know that the position of the spur varies considerably in var. communis. Hence, although the spur, on an average, lies closer to the basi-scutal angle in this than in any other variety, even than in var. d’Orbignii, it would, I conceive, be preposterous to found a species on this one character. In the animal’s body, every part agrees perfectly with that of var. communis.

Lastly, we come to var. d’Orbignii (Pl. 1, fig. l): until quite recently I did not even suspect that this form was only a variety of B. tintinnabulum: I have examined a great number of specimens in Mr. Stutchbury’s collection, which had come attached on a vessel from Java, and likewise a few other specimens in other collections. They all closely resemble each other in shape, and even in size, and differ only in tint of colour, and in the surface being either very smooth, or longitudinally ribbed, sometimes with rugged, sharp points. From this circumstance — from the peculiarity of the tint, with the tips of the parietes and one side of the radii perfectly white — and from the obliquity of the summits of the radii, I was led to think this form specifically distinct. But the colour does not differ from that of some other varieties of B. tintinnabulum; the circumstance of the colour being uniform or not striped, is common to the sub-varieties of several varieties, and the white tips to the parietes, and the white borders to the radii, result simply from the shell, whilst young, having been wholly white, and this is not rarely the case with var. communis. Dismissing, therefore, colour, it will be found that hardly any other characters remain by which this form can be separated from var. occator; in both the summits of the radii are oblique, in both the sheath is coloured in nearly the same manner, in both the opercular valves, especially the terga (Pl. 2, figs. 1 m, 1 n), resemble each other; the scuta, however, are smooth in var. d’Orbignii and rough in var. occator. This latter form, certainly, cannot be specifically separated from var. intermedius, and this assuredly is only a variety of B. tintinnabulum. Hence I am led to conclude that Balanus d’Orbignii of Chenu, peculiar as its whole aspect is, must be ranked only as a variety of B. tintinnabulum; its oblique radii resulting from the same cause, whatever that may be, which has given this structure to var. intermedius and occator; and its peculiar colouring to having been exposed (owing probably to having been transported on vessels) to different conditions, whilst young and old.

 

2. BALANUS TULIPIFORMIS. Pl. 2, fig. 2 a-2 d.

BALANUS TULIPIFORMIS EX CORALLIO RUBRO. Ellis. Philosoph. Transactions, vol. 50 (1758), tab. 30, fig. 10.

LEPAS TULIPA. Poli. Test. utriusque Siciliæ, tab. 5, fig. 1. et 6 (1791).

BALANUS TINTINNABULUM (var.) Chenu. Illust. Conch., tab. 3, f. 5.

According to the letter of the Rules of the British Association, Ellis’s name ought to be retained, as it was published in 1758, the same year during which the 10th edition of the ‘Systema Naturæ’ appeared, in which edition the binomial method was first used. But as Ellis himself did not then know of, or follow this method, it might be disputed whether, according to the spirit of the law, his name ought to stand. The only other name given to this species is that of tulipa, affixed by Poli in 1791, but this name had been previously used by Müller in 1776, and by Chemnitz in 1785, for another species, the B. Hameri of this work; and likewise, also previously to Poli, by Bruguière in 1789, for still another species, viz., B. tintinnabulum of this work: under these complicated causes of confusion, I think it is highly advisable to adopt Ellis’s name. I may add that the B. tulipa of Mr. G. B. Sowerby is the B. tintinnabulum of this work. It is possible that the B. conoides of Brown, ‘Illustrations Conch.’ (1st edit. pl. 6, fig. 7), may be our present species; but without details of structure it is hardly possible to identify, in many cases, the species of Balanus.

 

Shell dark rose-coloured, sometimes tinged with purple; orifice toothed. Scutum externally very smooth, covered by membrane. Tergum with distinct crests for the depressor muscles.

Hab. — Sicily, Malta, Malaga, (associated with B. perforatus), Madeira. Often growing in clusters and associated with Pachylasma giganteum. Attached to Millepora aspera, oysters, and other shells. According to Poli, an inhabitant of deep water; yet in mus. Cuming there are two fine specimens attached to the always floating Lepas anatifera. Mus. Lowe, Macandrew, Stutchbury.

General Appearance. — Shell tubulo-conical or conical: orifice large, toothed, approaching to pentagonal. Surface moderately smooth, naked. Colour rosy, or tile-red, with a slight tinge of purple; or beautiful rich purple. Radii nearly as dark as, or darker than, the parietes. The portion of the alæ seen externally is generally white. Internally the whole shell is nearly white. Generally the tints outside vary in transverse fasciæ; sometimes there are very fine, dark, longitudinal lines. Largest specimen (from Malta), 1.4 of an inch in basal diameter; usually full-sized specimens are about three quarters of an inch in basal diameter.

Scuta (Pl. 2, fig. 2 a, 2 c) very smooth, with the growth-ridges very little prominent, sometimes there are obscure traces of longitudinal striæ; surface covered by an unusually thick and persistent yellow membrane: valve narrow, with the upper part commonly reflexed: the basal margin forms, with the occludent margin, a smaller angle than is usual: the tergal margin of the valve is rectangularly inflected, instead of being, as is usual, merely bowed inwards. Internally, the articular ridge is rather prominent. The depth of the slight pit for the lateral depressor muscle is variable; it sometimes includes a minute, central, longitudinal ridge.

Terga (2 b, 2 d): the longitudinal furrow is deep, with the sides folded in; the spur is placed at about its own width from the basi-scutal angle; it is moderately long, with its lower end obliquely rounded off; but the length, breadth, and precise outline of the lower end varies a little. The basal margin on the opposite sides of the spur, forms a nearly straight line, but with the portion on the carinal side very slightly hollowed out. Crests for the depressor muscle are well developed.

Compartments. — The radii and alæ always have their summits oblique: the sutural edges of the radii are deeply penetrated by pores between the strongly denticulated septa: the sutural edges of the alæ are quite smooth: the tubes in the parietes are crossed in the upper part of the shell by septa. Basis tubular, with an underlying cancellated mass.

Mouth. — Labrum with the teeth either absent or very small: mandibles with the fourth and fifth teeth rudimentary: maxillæ with a small notch under the two upper spines; near the lower angle, two spines, one beneath the other, are larger even than the upper pair; beneath the lower pair, there is a tuft of fine spines. Cirri, segments protuberant in one ramus of the first cirrus and in both rami of the second cirrus; posterior cirri with the segments short and broad, each bearing three pairs of spines, with a small intermediate tuft.

Affinities. — This species in all essential respects comes very near to the three last varieties of B. tintinnabulum, which have the orifices of their shells toothed. The smoothness of the scutum, with its persistent epidermis, — its peculiar shape, — its small and not reflexed articular ridge, — together with the crests on the tergum for the depressor muscles, are sufficient diagnostic characters. Even in general habit and tint of colour, this species has a different aspect from B. tintinnabulum. In some respects B. tulipiformis leads into the species included in the third section of the genus.

 

3. BALANUS PSITTACUS. Pl. 2, fig. 3 a-3 d.

LEPAS PSITTACUS. Molina. Hist. Nat. Chile (1788), vol. i, .

BALANUS PICOS. Lesson. Zoolog. Voyage de la Coquille (1829).

  ——  — TINTINNABULUM (var. c). Ranzani. Mem. di Storia Nat. tab. 3, fig. 1-3 (1820).

  ——  — CYLINDRACEUS. Lamarck, in Chenu. Illust. Conch. Tab. 4, fig. 17, Tab. 5, fig. 7, sed non var. (c.) in Lamarck, Animaux sans Vert., (1818).

  ——  — PSITTACUS. King and Broderip. Zoolog. Journal, vol. v (1832-1834), .

Shell, pale dirty pink; orifice hexagonal. Scutum with the articular ridge very small, confluent with the very prominent adductor ridge, forming a tubular cavity, which extends up to the apex of the valve. Tergum with the apex produced, needle-like, purple: spur placed at less than its own width from the basi-scutal angle.

 

Hab. — Peru, Chile, Chiloe, Patagonia. Fossil in an ancient tertiary deposit, Coquimbo; and in a superficial, recent bed at S. Josef, in Patagonia.

General appearance. — Shell either almost cylindrical or steeply conical, generally flesh-coloured, sometimes pale pink; surface either smooth (when not disintegrated) or sometimes with the parietes distinctly and rather strongly ribbed, with the ribs distant from each other: I have seen six or seven ribs on the rostrum alone. The orifice in the most perfect specimens is nearly equilateral and hexagonal. The radii generally are very broad, but occasionally quite narrow, and even linear. The basis is generally deeply and irregularly cup-formed.

Size. — This is the largest species in the family: I have seen a specimen six inches in length and three and a half in diameter; and another specimen no less than nine in length, though only two and a half inches in diameter.

Scuta. — In full-sized specimens the surface is finely striated longitudinally, caused by the lines of growth being minutely sinuous; but in young specimens, until they attain a basal diameter of above half an inch, the surface is smooth. The valve is transversely arched, a line of flexure running from the apex to the basal margin, at about one third of the width of the valve from the tergal margin. The basal margin is curved nearly continuously, and extends nearly half-way up the valve; hence the basi-tergal corner is largely rounded off. The articular ridge is but little prominent, and is not reflexed: the articular furrow is very narrow. The adductor ridge consists of a sharp, much-projecting plate, running down close to the basal margin, and is confluent with the lower part of the articular ridge. This plate and the inflected tergal margin of the valve, together form a large and deep cavity, which extends up almost to the apex of the valve. The depressor muscle is attached in the middle, at the lower, open end of this cavity.

Terga. — These are strongly beaked, the beak being from one third to one fourth of the total length of the valve, including the spur: the beak is very sharp, somewhat flattened, and bowed; when young, and when well preserved, it is coloured purple: it is penetrated by a fine tubular cavity, occupied by a thread of corium, which extends about half-way up it. The whole valve is narrow, being about thrice as long as wide. The spur is also long and narrow; it is seated at less than its own width from the basi-scutal angle. The scutal margin is not much inflected. The longitudinal furrow has its sides, in full-grown specimens, closely folded together. The basal margin slopes down on both sides to the spur. There are no crests, or only traces of them, for the attachment of the depressor muscle. Internally, the spur is prolonged, as a prominent ridge, upwards to the beak, and serves as an articular ridge. In the middle, in the upper part (Pl. 2, fig. 3 d), between this articular ridge and the carinal margin, there is a second narrow ridge, which extends from the lower part of the beak half-way down the valve, and then dies out. The space between these two ridges, and the ridges themselves, are coloured purple, and consist of harder shell than the rest of the valve; hence, when the outer surface and the adjoining scutal and carinal margins disintegrate, this part remains, and so forms the beaked, purple apex.

Compartments. — The parietal tubes are unusually large in proportion to the size of the shell, and run up to the summit without any transverse septa: the longitudinal septa are strongly denticulated. The radii are penetrated by large tubes; their septa are very strongly denticulated, and the denticuli themselves often subdivide and branch out at their extremities. The sutural edges of the alæ are smooth, or with a high power can just be seen to be crenated. The radii are generally very highly developed, so that their summits are even wider than the bases of the parietes; but, on the other hand, in some few large specimens, the radii are either very narrow or absolutely linear. In these latter cases, the diametric growth has nearly or altogether ceased, whilst the walls of the shell have continued to be added to at their bases, their summits at the same time suffering disintegration; and thus the orifice has increased in size.

Basis generally, and occasionally very deeply, cup-formed. An unusually thick cancellated layer in most cases forms the under side of the basis.

Mouth. — Labrum apparently without teeth, or with very minute ones: mandibles with three teeth, of which the third is thicker than the first or upper one: the fourth and fifth teeth are confluent with the inferior angle. The maxillæ have a small notch under the upper pair of spines; inferior part projecting and supporting two spines, placed one below the other, and equalling in size the upper pair. Cirri: the rami of the first cirrus are unequal by four or five segments; shorter ramus and both rami of the second cirrus with the segments extremely protuberant: posterior cirri not much elongated, with the segments rather broad, supporting six pairs of spines.

General Remarks. — This, which is much the largest known species of the genus, ranges from Peru (Arica being the most northern spot, whence I have seen specimens), along the coast of Chile, where it is very abundant at a few fathoms’ depth, at least as far south as Southern Chiloe; it is said by Captain King to attain the largest size at Conception. On the coast of Eastern Patagonia, I dredged up this species from nineteen fathoms, in lat. 49°. In lat. 42° (S. Josef), on the same eastern coast, I found fossil specimens in beds of sand upraised between eighty and one hundred feet. In the tertiary formation at Coquimbo, in Chile, it occurs in the middle bed, associated with the recent B. lævis, and with various mollusca, all of which are apparently extinct, indicating that the formation is of considerable antiquity. In the living state, on the coast of Chile, it is often associated with B. lævis. As it frequently adheres to large specimens of the Concholepas, it must sometimes be an inhabitant of shallow water. I have seen one specimen attached to Mytilus Magellanicus. Mr. Cuming believes that about six fathoms is the usual depth at which it lives. Numerous specimens are often congregated together into great masses. Mr. Stutchbury has some interesting specimens which he procured from a ship that had first sailed to Ichaboe, on the coast of Africa, and afterwards to Patagonia; consequently numerous specimens of B. psittacus had become attached on B. tintinnabulum, and subsequently during the voyage home, some few of the latter again had adhered on B. psittacus: the contrast in the paler colour and hexagonal orifice of this species, with the darker tints and more trigonal orifice of B. tintinnabulum was striking. At Coquimbo, in Chile, I procured a specimen of B. psittacus, attached to a chain cable which had been in the water only six months; this specimen measured 1.3 of an inch in basal diameter, and .8 in height: this shows a rapid rate of growth. Lastly, I may mention that it is asserted by Molina, and I am assured by Mr. Cuming that the statement is perfectly correct, that this Balanus, when cooked, is universally esteemed as a delicious article of food.

 

4. BALANUS CAPENSIS. Pl. 2, fig. 4 a, 4 b.

BALANUS CAPENSIS ORE OBLIQUO. Ellis. Phil. Transact., vol. 50 (1758), Tab. 34, fig. 14.

Shell shaded, and often longitudinally striped with bright pink. Scutum as in B. psittacus. Tergum with the apex produced and needle-like, white: spur placed at its own width from the basi-scutal angle.

Hab. — Cape of Good Hope. Attached to stems of Fuci, Algoa Bay. Mus. Brit. and Bowerbank. Attached to a Patella, Mus. Darwin, Mus. Cuming, and Stutchbury. Attached to floating kelp, Lagulhas Bank, Mus. James Ross, associated with B. tintinnabulum and spongicola.

This species comes extremely close to the South American B. psittacus, and I should hardly have attached a specific name to it, had I not examined many specimens, young and old, of the true B. psittacus, from Peru, Chile, and Eastern Patagonia, and found them all identical in the few, apparently trifling points, in which that species differs from B. capensis. The animal’s body and the shell agree in every respect, excepting that the shell is decidedly pinker, being often most distinctly and prettily striped longitudinally with pale and bright pink. In some of the specimens the basis is cup-formed: in some, the broad radii are pale pink, in others they are quite white, and in this latter case a singular aspect is given to the pinkish varieties. In very large specimens (and I have seen one fully two inches in basal diameter) the pink colour is extremely feeble, and the whole shell has a very rugged, disintegrated, coarse, and sometimes dirty appearance: in most of these large specimens the walls are more massive than in B. psittacus, and the orifice of the shell rather smaller; in some, however, the walls certainly are of unusual thinness.

The Scuta differ from those of B. psittacus only in the basi-tergal corner not being so much rounded off, and consequently in the articular ridge, which is rather more reflexed, descending in proportion lower down the valve: the cavity at the basi-tergal corner is in proportion broader. The valves in the two species differ, also, but only in young specimens, in the occludent half being tinted, both externally and internally, purple, whereas in B. psittacus the whole valve, at all ages, is white. In the terga the spur is removed fully its own width from the basi-scutal angle, whereas it is not half this distance in B. psittacus. The scutal margin is here much more inflected. In B. psittacus there is a remarkable patch of purple on the inside of the valve, between the articular ridge and a second special ridge; of this purple patch there is here no trace, consequently the beak or apex is white. The beak, also, is less prominent. The special ridge, just alluded to, here runs much nearer to the articular ridge, and is less prominent: indeed, in old specimens, it is often almost obliterated. Finally, the whole valve, in proportion to the Scutum, is rather broader.

I have seen a young specimen, about a quarter of an inch in basal diameter, with the orifice of the shell toothed owing to the obliquity of the summits of the radii; and this gave the shell a very peculiar aspect. The largest well-coloured specimen which I have seen is 1.2 of an inch in basal diameter; but in Mr. Cuming’s collection there are two rugged, disintegrated specimens, two inches in basal diameter, and two and a half in height. Some specimens, 1.3 in basal diameter, in Mr. Stutchbury’s collection, are remarkable from the radii having been obliterated — the shell being merely divided by six sutures, as we have seen is likewise sometimes the case with large specimens of B. psittacus.

This species is evidently a South African representative of the South American B. psittacus.

 

5. BALANUS NIGRESCENS. Pl. 2, fig. 5 a, 5 b.

BALANUS NIGRESCENS. Lamarck, (1818) in Chenu. Illust. Conch., Tab. 4, fig. 16.

  ——  — GIGAS. Ranzani. Memoire di Storia Nat., 1820, Tab. 3, fig. 5, 6, 7.

 ——   ——  — De Blainville. Dict. des Sc. Nat., Tab. 116, fig. 2, 2 a.

Shell cinereous, tinted with pale or blackish blue, or wholly white. Scutum with the articular ridge terminating downwards in a small, sharp, free point: adductor ridge prominent. Tergum with the apex produced and needle-like.

Hab. — Swan River, West Australia, Mus. Brit., attached to sandstone. Attached to sandstone and to each other in a group, Mus. Cuming. Twofold Bay, S. E. Australia, attached to tidal rocks and Patellæ, Mus. Darwin.

 

There can be no doubt that this species is the B. nigrescens in Chenu, who had access to Lamarck’s original specimens; and there can be equally little doubt that it is the B. gigas of Ranzani, collected, during Baudin’s expedition, at King George’s Sound: it is essentially allied to B. psittacus, but in external appearance strikingly resembles some of the varieties of B. tintinnabulum.

General Appearance. — Shape tubulo-conical: walls smooth, sometimes longitudinally ribbed: colour ashy-gray tinged with blue, but many specimens are dark purplish-blue, owing to the disintegration of the outer lamina, and consequent exposure of the almost solidly filled up, dark blueish parietal tubes; on the other hand, some specimens are quite white. Ranzani describes the colour as earthy-violet, which is very characteristic of some of the specimens. The orifice is apt to be rather small, compared to the size of the specimens, and tends to be hexagonal. The radii are often rather narrow. The opercular valves are tinted pale blue. The basal diameter of the largest specimen is two inches, and its height two and a quarter.

The Scuta have their basi-tergal corner much rounded off, as in B. psittacus, so that the tergal margin does not extend more than half down the valve. The surface is somewhat prominent, along a line running from the apex to the point of chief curvature in the basal margin. The surface is not striated. Internally, the articular ridge is little prominent, and not reflexed; the lower end depends as a free, sharp style or point. The adductor ridge is moderately sharp, and stands some little way distant from the articular ridge: it is produced downwards, and forms a moderately deep and large cavity for the depressor muscle; but this cavity is not closed, and does not extend up, as in the two last species, to the apex of the valve.

Terga, narrow, with a sharp, prominent, needle-like beak. Spur, long, narrow, placed at less than its own width from the basi-scutal angle: the basal margin on both sides slopes down to the spur: the scutal margin is not inflected. Internally, the articular ridge is very feebly developed, but extends down close to the basi-scutal angle. On the under surface in the upper part of the valve, there is a short, very slight ridge, extending on the carinal side, near and parallel to the articular ridge; this slight ridge plays an important part, as in the two foregoing species, in the formation of the beak or apex. Crests for the depressor muscle are hardly distinguishable.

The Walls appear to vary in some degree in strength and thickness; as is likewise the case with the opercular valves. In some of the thinner specimens, the parietal tubes are large, and the longitudinal septa are furnished with small, sharp denticula. The tubes are often thickly lined or almost filled up solidly with blue shell; they are not crossed by transverse septa.

The Radii vary in width; externally they are often finely ribbed transversely, at other times they are smooth; their septa are fine and thin, with their delicate denticuli not extending to the outer lamina: they are very porose. The alæ have their summits parallel to the basis; their sutural edges are most finely crenated. The sheath is blueish, excepting the wedge-like portions of the alæ which have been added during the diametric growth, and these are white.

Mouth: labrum without teeth: mandibles with five sharp teeth: maxillæ with the edge straight. Cirri, first pair with the rami very slightly unequal; segments of the shorter ramus and of both rami of the second pair protuberant: posterior cirri with the segments shield-shaped in front, bearing four pairs of spines, of which the upper pair is much longer than the lower pairs; each pair has a small intermediate tuft of minute spines.

 

6. BALANUS DECORUS. Pl. 2, fig. 6 a, 6 b.

Parietes pale pink; radii rather darker. Scutum with a small articular ridge. Tergum with the longitudinal furrow very shallow and open; basal margin on both sides sloping towards the spur.

Hab. — New Zealand. Mus. Brit., and Flower: attached to shells.

General Appearance. — Shell conical or tubular, with a large rhomboidal orifice; very pale pink, but tinted yellowish from the persistent epidermis, and sometimes faintly striped longitudinally; radii and sheath of rather a darker pink; scuta in themselves white, though lined by purple corium; the carinal half of the tergum pink. Walls extremely smooth. Largest specimen above one inch in basal diameter.

Scuta, with the finest striæ radiating from the apex; growth-ridges moderately prominent; articular ridge small; there is a very slight and blunt adductor ridge: the hollow for the lateral depressor muscle is rather narrow and deep.

Terga, with the apex slightly prominent or beaked; the longitudinal furrow is of very little depth; on its scutal margin there is a narrow, rounded, slightly prominent ridge, which, however, appears more like a furrow than a ridge. Spur moderately long and blunt; placed at half its own width from the basi-scutal angle; the basal margin on both sides of the spur, slopes gently towards it. Internally, the articular ridge is pretty well developed; the scutal margin is not much inflected; the carinal portion of the under surface of the valve is rough; the crests for the carinal depressor muscle are entirely absent.

Compartments. — Walls moderately strong; parietal tubes small, with transverse septa in their upper ends; inner surface of the walls much less strongly ribbed than is usual. Radii broad, with their summits parallel to the basis; their septa are strongly denticulated. Alæ with their summits oblique; their sutural edges are barely crenated. Basis, thin, flat, or cup-formed. Body unknown.

Affinities. — In general appearance this species comes near to B. psittacus; but in all essential characters it comes much closer to the following species, from which, however, it can easily be distinguished by colour, and by the inner lamina of the parietes not being cancellated.

 

7. BALANUS VINACEUS. Pl. 2, fig. 7 a-7 d.

Shell purplish dark brown: inner lamina of the parietes cancellated. Scutum finely striated longitudinally. Tergum with the longitudinal furrow shallow and open; basal margin on both sides sloping towards the spur.

Hab. — West Coast of South America. Mus. Cuming.

General Appearance. — Shell conical, with a large, rhomboidal orifice; walls rather thin, coloured, together with the radii and operculum, dark purplish-brown; sheath nearly colourless. Walls smooth, slightly irregular, very finely striated longitudinally. Basal diameter of largest specimen .8 of an inch.

Opercular Valves, unusually smooth, that is without prominent growth-ridges. Scuta, finely striated longitudinally, with the sharp striæ closely approximate. The teeth on the occludent margin are sharp, and stand some way apart from each other. Internally, the whole surface is remarkably flat and smooth: the articular ridge is of moderate breadth, and slightly reflexed: there is no adductor ridge, and the oval depression for the lateral depressor muscle is extremely slight. Terga, with the longitudinal furrow very slight; the bottom of this furrow is feebly striated longitudinally, and there is a trace of a fine, rounded ridge on the scutal margin, as in B. decorus. The basal margin slopes on both sides towards the spur, which is of moderate length and breadth, with its lower end truncated and parallel to the carino-basal margin; the spur stands at about once and a half its own width from the basi-scutal angle. Internally, the valve is lined by very dark, purplish-brown corium; the articular ridge is prominent; in the upper part of the valve, parallel to the articular ridge, there are two or three feeble ridges; there are no crests for the tergal depressores.

The Parietes, though moderately thick, yet are light and fragile; the denticuli at the bases of the longitudinal septa are prominent, and those on the adjoining septa are united together, making a network (Pl. 2, fig. 7 d), but the interspaces between them are not filled up by solid calcareous matter (as is the case with every other species of the genus), but are only crossed at successive levels by fine transverse calcareous septa; the internal lamina thus becoming cancellated, and, though thick, fragile. Hence, in a transverse section of the parietes, the ordinary parietal tubes or pores are seen to be lined on their inner sides by five or six rows of very minute pores. I have not seen any other instance of this structure. The internal lamina is ribbed, as usual, on its inner surface, by the projection of the longitudinal septa. The ordinary parietal tubes are open, to nearly the summit of the shell. The radii are rather thin, and unusually fragile; their summits are parallel to the basis: their septa, as seen on the sutural edges, are extremely thin and denticulated on both their upper and lower surfaces, on the side towards the internal lamina: towards the external lamina, the septa are simple, and the small square pores thus formed, are open or not filled up. The alæ have their summits extremely oblique, being added to very little during the diametric growth of the shell; the narrow margin, however, which is thus added, is coloured red, the rest of the sheath being nearly colourless: the sutural edges of the alæ are smooth. The basis has a thick, underlying, finely cancellated layer of shell.

Animal’s body unknown.

A young specimen, .2 of an inch in basal diameter, differed from the above in being of a much paler purplish-brown. This species is distinct from all its congeners, in its peculiar colour, and likewise in the structure of the inner lamina of the parietes. As already stated, it comes nearer to B. decorus than to any other species.

 

8. BALANUS AJAX. Pl. 3, fig. 1 a-1 d.

BALANUS TINTINNABULUM (var.) Chenu. Illust. Conch., Tab. 2, fig. 8.

Shell globulo-conical, often elongated in the rostro-carinal axis, pale pink, smooth, extremely massive: parietal pores, close to the basal margin, circular and very small. Scutum with the articular ridge broad and reflexed.

Hab. — Philippine Archipelago, attached to Millepora complanata, Mus. Cuming. Mus. Brit. and Stutchbury.

General Appearance. — Shell globulo-convex, sometimes much elongated in its rostro-carinal axis; smooth; walls excessively strong, massive, and heavy. Orifice oval, rather small in proportion to the size of shell, this being chiefly due to the infolding of the upper part of the rostral compartment. Parietes pale pink, feebly tinted with purple: radii either paler, or tinted of a bright chesnut-brown: sheath rich purplish chesnut-brown. Basal diameter of the largest specimen nearly 3-1/2 of an inch; height 2-3/4: another specimen had a basal longitudinal diameter of 2.9 of an inch, and a transverse diameter of only 1.6; this great difference in the two diameters being caused by the prolongation of the basal portion of the rostrum in the line of the branch of the Millepora, to which the shell had adhered; the height of this same specimen was 1.5; and the diameter of the orifice, both transversely and longitudinally, .75 of an inch.

Scuta, broad, feebly tinted with pink; exterior surface rough, with sharp hood-formed projections, arranged in straight lines radiating from the apex; an inflected portion of the valve along the tergal margin is not roughened. Internally (Pl. 3, fig. 1 d), the articular ridge is broad and reflexed. An adductor ridge can hardly be said to exist, but a slight prominence borders the gentle hollow in which the lateral depressor muscle is attached. The basal margin, on its inner face, is slightly toothed. Tergum white, with the narrow part of the valve, on the scutal side of the spur, rough with the little projecting hoods, like those on the scutum; the other and larger half is smooth: spur rather long, narrow, placed at twice its own width from the basi-scutal angle; on the carinal side, about half of the basal margin slopes down towards the spur. The longitudinal furrow is either quite or nearly closed. Internally, the spur is produced upwards on the valve, as a prominence: the articular ridge is not very prominent. There are no crests for the tergal depressor muscle.

Altogether the opercular valves strikingly resemble those of B. tintinnabulum, but all the characters above mentioned have not been observed in any one variety of this species; perhaps var. coccopoma comes nearest, both in the external appearance of the shell and in the structure of the opercular valves, to B. Ajax.

The Compartments are remarkably compact and solid; the parietal tubes are cylindrical and quite minute even close to the basis; they extend, however, nearly up to the top of the shell; the parietal septa at the basis are thick, and with blunt denticuli; the thickness of the walls in the upper part of the shell is excessive; in the lower part, it is also unusually great, owing to the thickness of the inner lamina, and hence the ribs, generally formed by the projection of the longitudinal septa on the inner lamina, are here visible only close to the basis. The radii are rather wide; their summits are parallel to the basis; the septa on their sutural edges are thin, straight, and closely approximate, and most symmetrically furnished with little denticuli of equal sizes on both sides: the interspaces are nearly filled up solidly, but with some pores still left open. In the upper part of the shell, the radii, like the walls, are of extraordinary thickness: the septa are transverse and horizontal, as seen externally by slight variations in the colour of the radii; internally, as seen in a vertical section of the shell, the septa dip inwards at an angle of above 45°. The alæ are thin, and have their summits oblique: their sutural edges are smooth. The pores in the basis are crossed by numerous transverse septa, and there is an underlying cancellated layer: the internal surface is very smooth.

Animal’s body unknown.

The strength of this Balanus is truly remarkable; and when, by repeated blows, a specimen which I was examining at last yielded, the radii broke sooner than separate at their sutures. In most of its characters, this species approaches B. tintinnabulum, and I believe has been included by Chenu as one of its varieties; but it comes almost equally near to B. stultus, to which it is much more closely allied in its habit of being attached to Milleporæ. By a close and unbroken chain of affinities, B. Ajax, through B. stultus, is connected with B. calceolus and its allies in section (B), which live attached to Gorgoniæ. Some of the specimens of B. Ajax, are almost as much elongated in their rostro-carinal axis, as are the species in section (B); and there is an affinity in the same direction in the smallness of the pores in the radii of B. Ajax; indeed, had the basis in this species been generally more boat-or cup-formed, I should have placed it as the first species in section (B), instead of, as at present, the last species in section (A). The intermediateness of the characters of B. Ajax has been one chief cause why I have rejected the genus Conopea, which was instituted by Say for the species living attached to Gorgoniæ.

 

Section B.

Parietes and basis sometimes permeated by pores, sometimes not: radii not permeated by pores: shell elongated in its rostro-carinal axis: basis boat-shaped: attached to Gorgoniæ and Milleporæ.

 

9. BALANUS STULTUS. Pl. 3, fig. 2 a-2 d.

Parietes and base porose: shell white, or faintly tinged with purple. Scutum with the basal margin protuberant in the middle. Tergum with the longitudinal furrow closed in the upper part: spur not closely adjoining the basi-scutal angle.

Hab. — Attached to Milleporæ, Singapore, Mus. Cuming. West Indies, Mus. Brit. — Mus. Stutchbury.

This specimen in the British Museum was purchased at the sale of the Rev. L. Guilding’s collection, and therefore it is not certain that this habitat is correct; but as it was sold in the same lot with a Cirripede certainly West Indian, and as the main collection was made in the West Indies, this habitat may, I think, be trusted.

I have considerable doubts whether it would not have been more correct to have placed this species in the last section, instead of where it now stands; it certainly is more closely allied to B. Ajax, especially in its operculum, than to the following species; yet the fact of the radii not being permeated by pores does not permit of its admission into the last section; and both in habits and structure it undoubtedly comes very near to the following species. Those varieties which are not much elongated, and which have the basis nearly flat, would certainly, if considered by themselves alone, not have gained admission into our present section.

General Appearance. — Shell conical, somewhat globular, more or less elongated in the rostro-carinal axis, owing to the basal production of the rostrum. Orifice, rather small, entire, oval, pointed at the carinal end. Radii moderately broad, with their summits parallel to the basis. Colour dirty white, often faintly tinged with purple; sheath, pale purplish-blue. Surface extremely smooth; the parietes are generally covered (as viewed through a lens) by a very thin, yellowish epidermis, giving to the whole a glistening, granular aspect: the radii are generally destitute of this epidermis, and are therefore of a dead white. The basis is concave, and sometimes deeply cup-formed; it is, however, not symmetrical; sometimes it is flat. Basal diameter of largest specimen, including the basis itself, 1.5 of an inch in the longitudinal axis; transverse diameter, 1 inch; the inequality in the length of the two diameters is rarely so great as in this unusually large specimen.

Scuta, externally very convex, with the growth-ridges extremely prominent; basal margin sinuous, the middle portion being prominent; this is best seen in young specimens (Pl. 3, fig. 2 d). Internally, the articular ridge is broad and reflexed. The adductor ridge in the upper part is almost confluent with the articular ridge; it runs down to the most prominent point of the basal margin; in young specimens it is sharp and prominent; in old specimens it is very blunt and little prominent. There is a rather deep hollow for the lateral depressor muscle. In young specimens there is a small, depending, blunt tooth at the basi-tergal angle, which helps to make the basal margin more deeply sinuous.

Terga, with the longitudinal furrow closed, except on the spur itself, where it is open. The spur is moderately long and broad, but varies in breadth; it is placed at rather less than its own width from the basi-scutal angle; its lower end is obliquely rounded; the basal margin on the opposite sides of the spur, together form a nearly straight line. The whole valve is rather broad. The crests for the tergal depressores are barely developed.

The Compartments have rather large parietal tubes; the septa are coarsely denticulated at their bases; the internal lamina is smooth, except close to the basis. The radii have their summits parallel to the basis; their sutural edges are formed of rather thick septa, which stand at an unusual distance apart from each other, and have perfectly symmetrical, minute denticuli on each side. The interspaces between the septa are filled up solidly to within a short distance of the surface; but yet not so completely as in the following species, and as in those in the succeeding sections of the genus; this is what might have been expected from the close affinity of B. stultus to B. Ajax, in which latter the radii are still permeated by pores, though smaller than is general in the species of our first section (A). The alæ have their summits extremely oblique, and their sutural edges, I believe, smooth. Basis porose, with an underlying, finely-cancellated layer.

Mouth: labrum with six small teeth; mandibles with the 3d tooth blunt; the 4th minute, and the 5th almost confluent with the inferior angle. Maxillæ with the edge straight and simple. Cirri partly destroyed; on each segment of the sixth pair there were five pairs of spines.

 

10. BALANUS CALCEOLUS. Pl. 3, fig. 3 a-3 e.

BALANUS CALCEOLUS KERATOPHYTO INVOLUTUS (?) Ellis. Phil. Trans., vol. 50 (1758), Tab. 34, fig. 19.

LEPAS CALCEOLUS (?) Pallas. Elench. Zooph., , (sine descript.) (1766).

CONOPEA OVATA (?) J. E. Gray. Annals of Philosophy, vol. x, 1825.

Parietes and basis porose. Scutum with the pit for the lateral depressor muscle small and deep.

Hab. — Attached to Gorgoniæ, West Coast of Africa. Tubicoreen, near Madras, (Dr. Johnston), associated with B. navicula. Mediterranean (?). Mus. Brit., Cuming, Stutchbury.

Fossil. Coralline Crag; Mus. S. Wood.

I must premise, with respect to the nomenclature of this and the three following quite distinct species, that in the published descriptions no allusion is made to any one of the characters by which alone they can be distinguished: hence I have been guided by geographical probabilities in assigning the specific name of calceolus to the present species, as Ellis’s specimens came from the Mediterranean; and that of galeatus to the North American and West Indian specimens, as Linnæus’ original specimens (according to a statement by Spengler) came from the West Indies. I have assigned new names to the two remaining East Indian species. I may here add that Spengler (‘Skrifter af Naturhist.’ 1 B, tab. 6, fig. 3, 1790) has described, under the name of B. cassis, an allied form attached to the Gorgonia placomus from the seas of Norway; but I do not believe that it is the same with our present species.

General Appearance. — The degree of elongation of the shell in its rostro-carinal axis varies considerably (3 a, 3 b): the elongation is due to the production of the rostrum and of the corresponding end of the basal cup. These two portions of the shell always form together an angle, and sometimes an acute angle, whereas in all the many specimens which I have seen, the carina and the carinal end (or heel) of the basis together form a straight line; yet I should not be surprised if this end of the shell was sometimes produced. The surface of the shell is smooth, or sometimes marked with very minute projecting points: it is almost always covered by the horny bark of the Gorgonia. The colour is either dull purplish-red or dull purple, with obscure longitudinal stripes, and often more or less transversely banded with white. The rostrum is either white or very feebly tinted, being always paler than the rest of the shell: the radii are usually paler than the parietes, and are sometimes white: the carinal end of the basal cup is tinted of the same colour with, but rather paler than, the compartments. The orifice is rather small compared to the shell, and nearly heart-shaped. The carino-lateral compartments are about one-third of the width of the lateral compartments. The shell is very strong, and the sutures resist the action of boiling caustic potash. The largest specimen which I have seen was .7 of an inch in extreme length, and under .25 in extreme breadth.

Structure of the shell and basis. — The parietes are permeated by quite distinct pores, — a character sufficient by itself to separate this from the following species; the longitudinal septa forming the tubes are slightly denticulated at their bases. The radii have their summits quite square, extending from apex to apex of the adjoining compartments. The alæ have oblique summits. The sutural edges of the radii have approximate septa, which are obscurely denticulated: the interspaces are filled up solidly, so that the radii are not porose. The basis is distinctly porose, by which this species can be distinguished from B. navicula and cymbiformis. The basis has a deep furrow on the under side, from clasping the thin horny axis of the Gorgonia: the basal point of the rostrum is also notched from the same cause, and, as a consequence, its upper surface becomes slightly furrowed along its whole length.

The Scuta have an articular ridge but moderately prominent, and only slightly reflexed; the basi-tergal corner is rounded off; there is no adductor ridge; there is a small, rather deep, distinct pit for the lateral depressor muscle. Terga; externally the surface is considerably depressed in the line of the spur. The spur is between half and one-third of the width of the valve: its lower end is square and truncated, or in some degree rounded; it is sometimes (3 e) dentated with a few, minute, sharp teeth. The articular ridge is but slightly developed; the crests for the depressor muscle are very feeble.

Animal’s body unknown.

 

 

11. BALANUS GALEATUS. Pl. 3, fig. 4 a-4 c.

LEPAS GALEATA (?) Linnæus. Mantissa altera Holmiæ, 1771.

CONOPEA ELONGATA. Say. Journal of Acad. Nat. Sci. Philadelphia, vol. ii, part 2, , 1822.

If I have assigned the specific title of galeatus to the wrong species, yet Say’s name of elongatus ought not strictly to be admitted; as the Lepas elongata of Gmelin is a Balanus, — probably a variety of Balanus crenatus. I may add, that as the Lepas galeata of Schröter (‘Einleitung in die Conch.’ &c.), was attached to a Gorgonia from the East Indies, it cannot be our present species, but probably is one of the three other allied species, which all occur in India.

Parietes not porose; basis porose. Tergum, with the apex square, caused by the great development of the articular ridge.

Hab. — Charlestown, South Carolina; Florida; West Indies; Central America; attached to Gorgoniæ; Mus. Brit., Agassiz, Cuming, Stutchbury.

General Appearance. — This and the two following species come so close in general appearance to the last, that it will be quite superfluous to do more than describe the few points of difference. The shell and basis are generally quite as much elongated as in the last species, and sometimes much more so, owing to the carinal end (fig. 4 a), with the corresponding portion of the basal cup, being produced like the rostral end, into a flattened, sharp point: I have seen a specimen in this state .9 of an inch in length, and only .25 in breadth in the broadest part. In many specimens, however, the shape is exactly as in B. calceolus; but the rostrum seems less usually furrowed from clasping the stem of the Gorgonia. The colour is paler, pinker, and more distinctly striped longitudinally than in B. calceolus; I have, however, seen some not-striped, purple specimens (and one transversely freckled with white) from the West Indies. The parietes are strongly-ribbed internally, and are not permeated by pores. The radii have their sutural edges crenated. The basal cup is permeated by pores.

The Scutum differs from that in the last species, only in the pit for the lateral depressor muscle, being much shallower, and less defined, and in the apex being truncated. The Tergum is remarkable from its broad, square, truncated summit, which underlies the whole broad apex of the scutum: the square summit of the tergum is formed by a great and peculiar development of the uppermost part of the articular ridge. The spur is a little narrower than in B. calceolus.

Mouth: on the crest of the labrum there are two teeth on each side of the central notch. The mandibles have five teeth, of which the two lower are very small. The maxillæ show a trace of a notch under the upper large pair of spines; near the inferior angle there are two long spines. Cirri: in the first pair, one ramus is nearly twice as long as the other: the segments are not very protuberant. There is a sharp point at the dorsal basis of the penis. The branchiæ are of moderate size, and plicated on one side.

 

 

12. BALANUS CYMBIFORMIS. Pl. 3, fig. 5 a, 5 b.

Parietes and basis not porose. Scutum and Tergum with very small articular ridges. Tergum broad, almost equilateral.

Hab. — Attached to a Gorgonia, Tubicoreen, near Madras, (Dr. Johnston). Hab. unknown, Mus. Cuming.

General Appearance. — I have seen only two specimens, kindly sent me by Dr. Johnston, and a single specimen in Mr. Cuming’s collection. In most points this species agrees with the two last species. The shell (excepting the rostrum), and even the opercular valves in Mr. Cuming’s specimen were of a very fine purplish-red; in the other specimens they were feebly tinted purple. The parietes are strongly ribbed internally, and are not permeated by pores. The basal cup is not porose, but its inner surface is ribbed in lines radiating from the centre, and in both these respects this species differs from the two foregoing. The Radii are rather narrow; they are paler coloured than the parietes; they have their sutural edges plainly crenated. The alæ have extremely oblique summits; the narrow rim added during the diametric growth of the shell is white, the rest of the sheath being, in Mr. Cuming’s specimen, finely coloured like the parietes. Basal diameter of the longer axis of the largest specimen, .4 of an inch.

Scutum, rather narrow, with the basi-tergal corner much rounded off; externally the lines of growth are little prominent. Internally, the articular ridge is extremely little developed, and not at all reflexed; there is no adductor ridge; there is a minute pit for the lateral depressor muscle, placed almost on the edge of the valve. The Tergum is broad, forming (the spur being excepted) an almost equilateral triangle. The articular ridge is remarkably little prominent, and placed close to the scutal margin. The spur is nearly half as broad as the valve, with its extremity or basal margin in one case obliquely truncated, and in another case nearly square.

Animal’s body unknown.

 

13. BALANUS NAVICULA. Pl. 3, fig. 6 a-6 d.

Parietes and basis not porose: carino-lateral compartments very narrow, and of nearly the same width from top to bottom: radii with their sutural edges smooth. Scutum externally striated longitudinally.

Hab. — Attached to Gorgoniæ, Tubicoreen, Madras (associated with B. calceolus), Dr. Johnston. Hab. unknown, Mus. Brit. and Darwin.

 

This is a very distinct form, though nearer to the foregoing than to the other species. Its separation from the sub-genus Acasta is quite artificial; its affinity to this sub-genus is shown by its weaker shell, non-porose parietes and basis; by the radii having their sutural edges smooth, and their summits not quite square; by the carino-lateral compartments being very narrow; by the less elongated basis, not furrowed, from not clasping the branches of the Gorgonia; and by the longitudinally striated scuta; nevertheless, from the similar habits, and from the graduated structure in the five foregoing species, it cannot be removed out of the genus Balanus. I have seen three sets of specimens of this species.

General Appearance. — Shell, sometimes with the rostrum, and sometimes with the carina, and corresponding portions of the basal cup, elongated; but not, apparently, to so great a degree as in the foregoing species; basis not furrowed, from not clasping the branches of the Gorgonia. Colour pale blueish-purple, with the radii whiter. The surface is studded with small calcareous points. The carino-lateral compartments are very narrow, not more than one tenth of the width of the lateral compartments; they are, moreover, scarcely wider at the base than at the summit. The summits of the radii are, apparently, a little oblique, or at least not so square as in the foregoing species. The shell is not nearly so strong as in the last three species; and the compartments separate by gentle force, and from the action of caustic potash. The largest specimen was .4 of an inch in basal diameter.

Internally, the parietes are not very strongly ribbed, or they are almost smooth, and there are no pores. The basis is concave and smooth within, and is not porose. The sutural edges of the radii are quite smooth, or sometimes they exhibit, in the lower part, mere traces of septa, — a character by itself sufficient to separate this from the foregoing species. The alæ have oblique summits, and the rather narrow portion added during the diametric growth of the shell, is white.

The Scutum, externally (6 d), has raised striæ, radiating from the apex; valve rather thick; internally, the articular ridge is but slightly prominent, and its lower end is rounded off: the depression for the lateral depressor muscle is slight; between this depression and that for the adductor muscle, the surface of the valve is prominent. Tergum, somewhat beaked; externally, the surface is depressed in the line of the spur: the carino-basal margin slopes towards the spur.

Animal’s body unknown.

 

 

Section C.

Parietes and basis permeated by pores. Radii not permeated by pores.

 

14. BALANUS TRIGONUS. Pl. 3, fig. 7 a-7 f.

Parietes ribbed, mottled purplish-red; orifice broad, trigonal, hardly toothed. Scutum thick, with from one to six longitudinal rows of little pits. Tergum without a longitudinal furrow; spur truncated, fully one third of width of valve.

Hab. — Java; East-Indian Archipelago; Peru; West Columbia; California; Sydney; New Zealand. Mus. Brit., Cuming, Stutchbury, Dunker, &c.

General Appearance. — Shell conical, generally depressed; orifice broad, triangular, almost equilateral; walls coloured or only mottled with purplish-pink, having either irregularly branching, or regular, longitudinal ribs, which are generally white. The radii are pale pink, or nearly white: the opercular valves have either their upper parts, or nearly their whole surface, clouded with pinkish-purple: the epidermis is not persistent: the walls are moderately strong: the largest specimen was one inch, but generally full-grown specimens are about half an inch in basal diameter.

The Scuta have the lines of growth highly prominent. From one to five or six rows (7 b, 7 c) of nearly circular, or transversely oblong, deep pits, extend down the middle of the valve; rarely there is not even one row; in this latter case, the valve is not striated longitudinally. These little pits are caused by one or more deep longitudinal furrows, crossed by the lines, or rather ridges, of growth. In the same group of specimens, I have seen individuals with three, five, and six rows; and even a few specimens with only one row, or none at all. The outline of the valve is elongated, with the apex slightly reflexed: the inner surface is protuberant, sometimes to a remarkable, but variable degree. The articular ridge is not very prominent, but it extends fully half-way down the valve, and generally ends in a small free point. There is a short adductor ridge, and a deep narrow pit or cleft for the lateral-depressor muscle. Terga, externally smooth, flat, with scarcely a trace of a longitudinal furrow; spur broad (7 e, 7 f), varying from half to one third of the width of the valve, with the end truncated, situated either near or quite close to the basi-scutal angle. The crests for the depressor muscles are moderately well developed.

Compartments. — The parietal tubes are, in their upper parts, filled up solidly, without transverse septa. The radii generally have their summits slightly oblique, and this is almost always the case with the radii of the rostrum; the other radii sometimes extend from tip to tip of the parietes, and are parallel to the basis; rarely the radii are considerably oblique. The septa of the radii are very obscurely denticulated, and the interspaces between them are filled up solidly. The alæ have their sutural edges thin and smooth.

Mouth. — Labrum with three teeth close together on each side of the central notch: mandibles with four teeth, the fourth being small, the fifth either absent or scarcely distinguishable from the inferior angle: maxillæ without any notch, with the two lower spines rather longer than the others. Cirri: In the first pair, one ramus is only half the length of the other; in the second pair, both rami are short and about equal in length; in the posterior pairs, the segments, which are not protuberant, bear four pairs of spines, of which the three lower pairs are short.

This species is widely-distributed, and where found seems to be common. It is generally attached to shells of mollusca, but I have seen it also attached to wood. I have found it associated with B. tintinnabulum, var. concinnus, and coccopoma, with B. psittacus, improvisus and amphitrite, and with Elminius modestus.

Young specimens bear a considerable resemblance to certain young varieties of B. tintinnabulum, and can indeed be distinguished from them only by a careful examination of the opercular valves; for it should be borne in mind, that in certain cases the scuta in B. tintinnabulum are pitted with little cavities. This species in some respects is, I think, allied to B. porcatus, but it is far more closely related to B. spongicola, and can be discriminated with difficulty from certain varieties of this latter species. In Mr. Cuming’s collection, there is a group of small specimens, crowded between some older specimens, which are remarkable from the shell being oval in a transverse section, — from the smoothness of the walls, — and from the absence of pits on the scuta; yet there could be no doubt that these specimens belonged to our present species.

 

 

15. BALANUS SPONGICOLA. Pl. 4, fig. 1 a-1 d.

BALANUS SPONGICOLA. Brown’s Illustrations of the Conchology of Great Britain (1827), pl. 7, fig. 6: 2d edit. (1844), pl. 53, figs. 14-16.

Parietes generally smooth, sometimes longitudinally folded; coloured pink: orifice toothed. Scutum longitudinally striated. Tergum, with the apex produced, without a longitudinal furrow; spur truncated, about one third of width of valve.

Var. with the walls slightly folded longitudinally.

Hab. — South coast of England, and Tenby in South Wales, often imbedded in sponges; attached also to shells and rocks in deep water; Mus. Brit., Jeffreys. Algiers, on Mytili and Serpulæ, with B. perforatus, Mus. Mac Andrew. Madeira, with B. tulipiformis, Mus. Lowe. Lagulhas Bank, Cape of Good Hope, on detached kelp, with B. Capensis, Mus. Sir J. Ross. Imbedded in sponge with Acasta spongites, Mus. Bowerbank. Var. West Indies.

Fossil in Coralline Crag, Mus. S. Wood.

General Description. — Shell tubulo-conical; orifice of moderate size, rather deeply toothed; colour dull pink, or purplish, or dark flesh-colour; sometimes the radii are paler, sometimes of the same colour with the parietes. Surface smooth when well preserved, having transverse rows of minute spines. In the West Indian variety the walls are slightly or much folded, but I will describe this form separately. Size of largest specimen (Mus. Jeffreys), .6 of an inch in basal diameter.

Scutum, with fine ridges radiating from the apex, and with the lines of growth, crenated: internally, the articular ridge is small, adductor ridge short and barely distinct: there is a rather deep and narrow pit for the lateral depressor muscle. The whole valve is much thinner than in B. trigonus, which in most respects it closely resembles. Tergum, with the apex pinkish purple, produced or beaked, but the beak is not needle-like, as in B. psittacus and its allies, for the carinal margin is perfectly preserved up to the tip. Externally the valve is nearly flat, for the longitudinal furrow is very shallow. The spur is about one third of the width of the valve; its lower end is abruptly truncated: in European specimens (1 b) the whole basal margin, on the carinal side, slopes down to the spur in a straight line, which, together with the sharpness and production of the basi-scutal angle of the spur itself, gives to the whole valve a peculiar appearance: in the specimen (1 c) from the Lagulhas Bank, the basal margin on the carinal side is a little more hollowed out, but it is quite impossible to doubt about the specific identity of these specimens: in the West Indian variety (1 d) the basal margin on the carinal side forms a distinct but obtuse angle with the spur. In all cases the crests for the depressor muscles are very feebly developed.

The Compartments have their radii developed to a rather varying degree, with their summits oblique; hence the orifice is toothed: the sutural edges of the radii have their septa barely denticulated; the sutural edges of the alæ are smooth. The basis, as with the other species of this section, is permeated by pores; yet I found one specimen, from the Cape of Good Hope, with the basis apparently solid, thus offering a very singular anomaly. In the specimen imbedded in sponge, the basis, as viewed externally, is concave; whereas in Acasta, which always inhabits sponges, the basis is highly convex or hemispherical.

The Mouth and Cirri resemble those of B. trigonus, and I can point out no distinguishing character.

With respect to the variety from the West Indies, I have seen two sets of specimens differing somewhat in external appearance, one set attached to a coral from St. Vincent’s, and another set to an Avicula from an unknown locality; at first I described these specimens, with some hesitation, as a distinct species, and I am very far from sure whether this would not have been the more correct course, although I am unable to point out any sufficient diagnostic characters. This form differs from the ordinary B. spongicola, in the walls being more rugged, stronger, and slightly or deeply folded longitudinally; in this latter case the shell in external aspect differs much from ordinary specimens of B. spongicola; but this is a variation so common that I dare not place any reliance on it. The colour is more purple; the summits of the radii perhaps rather less oblique. In the scuta the only difference is that the articular ridge seems rather longer, and the adductor ridge perhaps more prominent: in the terga, as already remarked, the basal margin on the carinal side does not slope so straight into the spur. These differences I consider all too slight to be of specific value. The difficulty in determining the nature of this variety is added to by its approach to B. trigonus in all those points in which it departs from the ordinary B. spongicola, so that for a short time I was even tempted to consider both these species as varieties of one form. But until B. trigonus is found with its scutum longitudinally striated, and with its tergum beaked, it can hardly be confounded with B. spongicola; for it should be observed that when in B. trigonus the rows of little pits disappear from the scuta, as sometimes happens, though rarely, yet these valves do not become longitudinally striated.

Balanus spongicola occurs, mingled with B. tulipiformis, in the Mediterranean, and by the external characters of the shell alone cannot be distinguished from that species; but the striated scuta and beaked terga suffice to separate them. Again, this species, at the Cape of Good Hope, occurs mingled with B. Capensis, and from the non-striped young varieties of that species, it can, externally, be distinguished only by the beak of the tergum not being sharp like a needle. I have seen a single, perfectly characterised specimen, with its opercular valves preserved, found by Mr. S. Wood in the Coralline Crag at Sutton, mingled with B. inclusus.

 

 

16. BALANUS LÆVIS. Pl. 4, fig. 2-2 g.

BALANUS LÆVIS. Bruguière. Encyclop. Meth. (1789), Pl. 164, fig. 1.

  ——  — DISCORS. Ranzani. Mem. di Storia Nat., 1820, Tab. 3, figs. 9 to 13.

  ——  — COQUIMBENSIS. G. B. Sowerby, in Darwin’s Geology of South America (1846), Tab. 11, fig. 7.

M. Deshayes, in his descriptions of the plates, considers this figure, I have no doubt erroneously, as that of B. perforatus, of Bruguière. The B. Coquimbensis of Sowerby, is a different species from the B. Coquimbensis, of Chenu, ‘Illust. Conch.,’ tab. 6, which latter is unknown to me.

Shell covered by brown membrane, or naked and white or pale purple; orifice small; radii very narrow. Scutum with one or two deep longitudinal furrows.

Var. nitidus (fig. 2): shell not covered by membrane, white or pale purple: orifice but slightly toothed: scutum generally with two furrows. Hab. — Chile, as far south as Concepcion; Peru; California.

Var. Coquimbensis (fig. 2 a): with the basal cup partly filled up with thin, irregular, calcareous layers, making a cancellated mass. Fossil, and recent.

Hab. — Strait of Magellan, ten to twenty fathoms, attached to shells; often entirely surrounding pebbles, forming globular masses; associated with Verruca lævigata. Chile and Peru, (generally var. nitidus), often attached to Balanus psittacus. California. Very common.

Fossil in an ancient tertiary formation (middle bed) at Coquimbo, Chile. In a recent deposit (var. nitidus) at the height of 1000 feet at Valparaiso; with Human remains at San Lorenzo, Callao, Peru.

I may premise that, having myself collected this species from the same locality, the Strait of Magellan, where no allied species occurs, attached to the same Mytilus and associated with the same Verruca, I feel confident that it is the B. lævis described by Bruguière; and there can hardly be any doubt that it is the B. discors of Ranzani. With respect to the old tertiary specimens from Coquimbo, named B. Coquimbensis by Sowerby, they differ from the recent in no respect, except in being considerably larger; and therefore I cannot consider them specifically distinct. At first I was unwilling to believe that the specimens with a single very broad longitudinal furrow, and those with two rather broad, or with one narrow furrow, on their scuta, could belong to the same species; but I soon found that all these varieties occurred mingled together, and that they differed in no other respect whatever. Generally, however, all the individuals in the same cluster had the same variety of scutum, — thus adding one more to the many instances amongst cirripedes of variations common to whole groups of specimens. Still more unwilling was I to believe that var. nitidus and the common variety could belong to the same species. Their general aspect is totally unlike: var. nitidus has a smooth, clean, naked shell, either white or pale purple, somewhat globulo-conical, often with a nearly entire orifice; whereas the other common variety generally has a more steeply conical shell, with a toothed orifice, and is covered by a dirty brownish membrane. Moreover, though I have seen hundreds of specimens from Tierra del Fuego, I have not seen one specimen of var. nitidus, or even of an approach to it in appearance; and, on the other hand, var. nitidus is the common form in Chile and Peru; though I have seen one or two specimens of the membrane-covered variety from Valparaiso. Such facts strongly induced me to believe that these forms were specifically distinct; but upon careful examination I could find no other or more important differences than those just specified. Some specimens from northern Chile are in an intermediate condition; and from Concepcion, in the south of Chile, where the climate approaches in character to that of the more southern parts of the Continent, there are many specimens, in so intermediate a condition that I know not whether or no to rank them under var. nitidus. Thus I became convinced that these forms are only varieties. At Concepcion, some few specimens are pale purple, and yet are wholly invested by thick brown membrane, thus uniting the two extreme varieties. From California I have seen both varieties, but I do not know which is most common there. With respect to the great difference in aspect between the specimens from northern Chile and Tierra del Fuego, we shall hereafter see a strictly analogous case in Balanus flosculus. Finally, I may add that B. lævis seems to represent in the southern hemisphere and on the west coast of North America, the B. perforatus of Europe and Western Africa.

General Appearance. — Shell conical, sometimes slightly globular; surface smooth (that is, not folded), either naked, and in that case white or pale purple, or covered by dirty yellowish-brown membrane. Orifice small, more or less toothed, rarely exceeding one third of the basal diameter. Radii very narrow, often not developed, the six sutures forming in all cases deep and narrow clefts. The largest recent, but much depressed, specimen which I have seen (from the Strait of Magellan) was three fourths of an inch in basal diameter; specimens growing congregated are often much elongated. I have seen one with the basal cup between two and three times as deep as the height of the compartments. Of the ancient tertiary specimens, the largest had a diameter of three fourths of an inch, and a total length of actually two inches (fig. 2 a); another of these fossils had a basal cup in depth equalling four fifths of the entire length of the shell and basis.

The scutum has either one very broad and deep longitudinal furrow (2 b), or two moderately broad and deep (2 e), or two narrow and deep, or less frequently one narrow and inconspicuous longitudinal furrow (2 f); rarely there is not one furrow; sometimes there are none towards the apex, whilst furrows have been formed in the lower part of the valve. In young specimens the furrows extend down to the actual basal margin, but in old specimens they often fall short of this, and, as a consequence, the furrows become crossed by one, two, or three calcareous ridges, which ridges at successive periods formed the basal margin of the valve. The external surface is covered by yellow membrane; and fragments of several successive opercular membranes are often attached to the zones of growth.

Internally the articular ridge is not very prominent, but is remarkable (2 c, 2 d) from its lower point being produced into a long, sharp, sub-cylindrical, free style (like the hinge of a common gate), which is generally broken off in disarticulating the valve from the tergum. The adductor ridge is either sharp and prominent or blunt: it extends up the middle of the valve nearly to the apex, and downwards it trends a little towards the occludent margin. The pit for the lateral depressor muscle is minute but deep: the basal margin is sometimes hollowed out under this pit. Sometimes there is a distinct, but blunt ridge, caused by one of the furrows outside, parallel to the adductor ridge, and placed between it and the little pit for the lateral depressor; in this case, the basal margin, as viewed internally, is rendered sinuous (2 d), as is best exhibited in the great fossil specimens from Coquimbo.

Tergum (2 g). — Spur of moderate length and breadth, with its lower end obliquely truncated and rounded. The longitudinal furrow has its edges somewhat folded in. The basal margin on the carinal side of the spur is sometimes a little hollowed out. The crests for the depressor muscles are well developed; but the corner of the valve supporting them is extremely thin, and is often imperfectly calcified.

Compartments. — The parietal tubes are not crossed by transverse septa, but in their upper parts are filled up solidly. The radii are always very narrow, with their summits oblique, though to a variable degree: their sutural edges have fine and closely approximate septa, with minute denticuli: the sutural edges are received in a furrow, on the opposed compartment, of unusual depth; hence the lines of suture run, in the lower part of the shell, almost exactly in the middle between each two compartments. The alæ are added to above the level of the opercular membrane.

The Basis is often thick, with an underlying layer, largely cancellated or honeycombed. When many specimens grow crowded together, the basis is generally deeply cup-formed, or even sub-cylindrical; and equals as much as four fifths of the length of the entire shell. In such cases, in some few recent specimens, and in all the large or even quarter-grown old tertiary specimens, but not in the quite young fossil specimens, a structure is presented, which I have not seen in any other Cirripede, namely, the basis (Pl. 4, fig. 2 a) is filled up for one third, or even for more than half its depth, by successive, separate, calcareous, transverse layers or septa. It would appear as if the basal cup had grown too large for the animal’s body, and so required filling up. The layers are thin and fragile; a single layer never stretches across the whole shell; each is irregularly mammillated or blistered, with the convex surfaces generally directed upwards; the layers are furnished on their under sides with little pillars and short ridges, resting on the layers beneath; it rarely happens that the supports of one layer lie directly over those of another, though this is sometimes the case. In a vertical section, the mass formed by these irregular layers has a coarsely cancellated structure. This structure, although confined to this one Cirripede, is not so anomalous as might at first be thought, for in most species of the genus, each time that the circumference of the basis is added to, an excessively thin calcified film is thrown down over its whole inner surface; and in any of these species, if the films had been formed thicker and had rested only on certain points, instead of over the whole underlying layer, the cancellated structure above described would have been produced.

Mouth: the labrum is either destitute of teeth, or has two or three very minute teeth. The palpi have a tuft of very long spines at their ends. The third tooth of the mandibles is thicker and larger than the two upper ones. The maxillæ have either a nearly straight edge, or the inferior corner is obliquely truncated, and projects much beyond the rest of the edge. In the Cirri, none of the segments are very protuberant: in the first pair, one ramus is nearly twice as long as the other: in the posterior pairs, the segments are not much elongated, but each supports seven pairs of spines.

Var. nitidus: with respect to this variety I have little to add to my preliminary remarks on its peculiar appearance, owing to its smooth, naked condition, and pure white or pale purple colour. This colour, when examined through a lens, is seen to consist of very fine longitudinal stripes; and is produced by the calcareous matter within the longitudinal parietal pores being thus coloured. Generally the scuta have two longitudinal furrows; but I have seen a scutum of one perfectly characterised specimen with only a single broad furrow, like that which frequently occurs in the membrane-covered variety. Var. Coquimbensis, as before stated, differs only in its greater size: the scutum, in the one specimen examined, had two broad longitudinal furrows; neither it, nor the tergum differed from certain varieties now found on the coast of Chile.

 

17. BALANUS PERFORATUS. Pl. 5, fig. 1 a-1 d; Pl. 4, fig. 3 a-3 c.

BALANUS PERFORATUS. Bruguière. Encyclop. Meth., 1789, Tab. 164, fig. 12 infra.

LEPAS ANGUSTA. Gmelin. Syst. Naturæ, 1789.

  —— ORE ANGUSTIORE. Chemnitz. Vol. viii, Tab. 98, fig. 835.

BALANUS CORNUBIENSIS CONICO ORE MINORE. Ellis. Phil. Trans. vol. 50, 1758, Tab. 34, fig. 16.

LEPAS BALANUS ET FISTULOSUS. Poli. Test. Siciliæ (1795), Tab. 4, fig. 5, Tab. 6, fig. 1.

BALANUS COMMUNIS. Pulteney. Dorset Catalogue, 1799.

  ——   ——  — Montagu. Test. Brit., 1803.

LEPAS ANGUSTATA. Wood. General Conchology, 1815, Pl. 6, fig. 5.

BALANUS CRANCHII. Leach (!). (B. Blainvillii in Tab.) Encyclop. Brit. Suppl., vol. iii, 1824.

  ——   ——  — Brown. Illust. Conch., 1827, Pl. 7, fig. 9, 10, and 2d Edit., Pl. 53, fig. 9-12.

  ——  — PERFORATUS. Chenu. Illust. Conch., Tab. 3, fig. 9, Tab. 6, fig. 15.

I have very little doubt regarding any of these references: I have no means of ascertaining the priority, within the same year, of Gmelin and Bruguière, but have given it to the latter, as perforatus is much the best known specific name. English conchologists seem generally to suppose that the B. communis of Pulteney and Montagu is the B. porcatus of this work; but I have not the smallest doubt that I have given it rightly as a synonym of the present species; the indistinctness of the compartments, the multitude of fine ridges, the smallness of the orifice, the longitudinal furrow on the terga, the colour, size, and habitat, all given by Pulteney or Montagu, will agree with no other British species. The Lepas balanus of Poli, which is certainly a synonym of our present species, has been erroneously considered by several authors to be the same with the L. balanoides of Poli, which latter undoubtedly is the B. amphitrite of this work.

Shell pale purple, or white, or dirty ash-colour; smooth, or, from being corroded, finely ribbed longitudinally; sheath purple; orifice generally small; radii generally narrow or absent. Scutum, internally, with a short minute ridge, parallel and close under the prominent adductor ridge. Tergum with the apex somewhat produced.

 

Var. angustus (Gmelin) Pl. 5, fig. 1 a: pale dull purple or white; orifice small or of moderate size; radii very narrow or moderately wide, white or pale purple, with oblique summits.

Var. Cranchii (Leach) Pl. 5, fig. 1 b: corroded, covered with fine longitudinal ridges owing to the exposed, filled-up, parietal tubes; dark dirty ash-colour, with a tinge of purple: radii not developed, or very narrow with oblique summits; orifice small.

Var. fistulosus (Poli) Pl. 5, fig. 1 d: shell cylindrical, white or dull purple; orifice of moderate size or small; basis deeply cup-formed.

Var. mirabilis, Pl. 5, fig. 1 c: bright purple; radii white, very broad, with their summits parallel to the basis; orifice entire, large.

Hab. — Southern shores of England; South Wales; Mediterranean; Western Africa, southward to Loanda, in 9° S.; West Indies (?). Generally adhering to rocks at a low tidal level; in one case attached to the floating Lepas Hillii, Mus. Jeffreys.

This is a well-marked species, and in its essential characters does not vary much; but owing to the shell being almost as often white as purple, — to its being remarkably subject to disintegration, — to its often becoming cylindrical, — to the radii being either not at all, or slightly, or moderately, or largely developed, and consequently to the orifice of the shell varying in size, the general external appearance of the different varieties is singularly diversified; but when a series of specimens is examined, it is easy to see how one form passes into another.

General Appearance. — Shell conical, with the orifice oval, unusually small, being generally only from one third to half of the basal diameter; sometimes moderately large; in one single instance as wide as the basis. Radii, often represented by mere lineal fissures, or they are narrow, or sometimes moderately wide. Colour pale, dull purple, sometimes lilac, often passing into a dead pure white: the same individual will occasionally have one part of its shell white, and another purple: the purple tint almost invariably is nearly uniform, or not in stripes. The radii are generally white, when the whole shell is purple, but sometimes they are pale purple: the sheath is apparently always coloured of a fine claret-purple, with the triangular portion of the alæ, added during diametric growth, generally white, but sometimes purple. The surface is quite smooth, but very often, especially on the shores of England, whole groups of specimens (excepting the very young ones,) have had the outer lamina of the parietes entirely corroded and removed; in this case the shell assumes a dirty, more or less dark, ash-colour, feebly tinted with purple, and the whole surface, owing to the exposure of the solidly filled-up parietal tubes, becomes finely striated, or covered with very narrow, longitudinal ridges. When specimens are crowded together they often become cylindrical, and much elongated, owing to the basis becoming deeply cup-formed: I have seen specimens, half an inch in diameter in the widest part, one inch and a half in height, the walls forming only a third of this. The largest specimen which I have seen (from the southern shores of England) had a basal diameter of 1.2 of an inch; some very steeply conical specimens were .9 of an inch in height, and .8 in basal diameter.

Scuta, externally, slightly convex; growth-ridges approximate, moderately prominent. Internally (Pl. 4, fig. 3 a) the articular ridge is moderately developed, with the lower end produced downwards into a freely depending, flattened style, somewhat variable in size, but not so long as in B. lævis, and easily broken in disarticulating the valves. The adductor ridge is very prominent, running from almost the apex of the valve, close to the articular ridge, to near the basal margin. The basi-tergal portion of the valve is converted by the adductor ridge into a rather deep cavity, within which there is a short, sharp, and minute ridge, close and parallel to the adductor ridge, and bounding the impression left by the lateral depressor muscle: this insignificant ridge was present in every specimen; it occurs only in very few other species, as in B. nubilus and cariosus. The thickness of the valve sometimes varies a little, and when thick the adductor ridge does not appear quite so prominent. Tergum, with the apex moderately beaked and produced; beak triangular in section, coloured dark purple, as is the upper internal surface of the valve; the longitudinal furrow is deep, and has its edges folded in, and even quite closed. The spur is moderately long and narrow; but its width varies a little (Pl. 4, fig. 3 b, 3 c), and consequently it stands at either rather above or at twice its own breadth from the basi-scutal angle: its lower end is either bluntly pointed or square, and generally is feebly toothed on the under-side. The basal margin of the valve generally slopes a little, on both sides, towards the spur. Internally, the scutal margin is but slightly inflected: the articular ridge is but slightly prominent, and but little curved; in the upper part of the valve there are generally several very minute ridges, parallel to the articular ridge, on the side towards the scutum. The internal surface of the spur itself is sometimes concave. The crests for the carinal depressor muscle are barely developed. It may here be mentioned that on the opercular membrane many long spines stand rudely arranged in rows.

Parietes: the parietal tubes have not transverse septa; but are solidly filled up in their upper parts by dark-purple layers of shell. The radii, as already stated, are either not at all developed, or are extremely or only moderately narrow, with their summits more or less oblique: in Mr. Cuming’s collection, however, there is an unique specimen, var. mirabilis (Pl. 5, fig. 1 c) with the aperture of the shell as wide as the basis, with bright purple parietes, and white, very broad radii, having their summits parallel to the basis. The septa of the radii are finely denticulated, and the interspaces are filled up solidly. The alæ have very oblique summits, and their edges are finely crenated. Basis, flat, or deeply cup-shaped; there is often an underlying, coarsely-cancellated layer.

 

Mouth: labrum finely hairy, but without any teeth; mandibles, with the 4th tooth small; the 5th confluent, with the sometimes smooth, sometimes pectinated inferior angle. Maxillæ, rather broad, with a slight notch under the upper pair of spines. Cirri, first pair, with one ramus, having 29 segments, and above one third longer than the shorter ramus, having 17 segments; these latter segments are remarkable by the extent to which their upper front surfaces are laterally produced into projections, twice as long as the breadth of that portion of the segment which is articulated to the adjoining segment. These projections have a double row of serrated spines on their upper edge, and a beautiful radiating bundle at the end; the projections decrease in length, both in the upper and lower segments. The second cirrus (Pl. 29, fig. 4) has the segments (13 in number, in the same individual with the segments above enumerated) of both rami produced in the same singular manner as in the first pair. The third pair have only inverted conical segments, coloured darker purple than the other cirri. The sixth pair had in the same individual 31 or 32 segments, and therefore one or two more than in the longer ramus of the first pair. The segments in the posterior cirri have their anterior faces shield-shaped, and bear 6 or 7 pairs of spines, with some minute intermediate spines. There is the usual point at the dorsal basis of the penis.

Under the Genus () I have given the numbers of the segments in the cirri of this species at successive ages.

Range. — This species is common on the southern shores of England and in the Channel Islands: the largest specimens which I have seen came from these quarters. The most northern point whence I have seen specimens, is Tenby, in South Wales. This species is common throughout the Mediterranean; I have seen specimens from Malaga, Sicily, Algiers, and Smyrna; thence it ranges down the western coast of Africa, as far south as the Gambia and Loanda, in 9° south latitude. I believe British specimens are more often corroded than those from further south. Amongst some old, ill-kept specimens in a box in the British Museum, marked “Kingston, Jamaica,” there were some of this species: also I received some specimens, marked “S. America,” from Mr. G. B. Sowerby: again, Ellis, in Phil. Trans., vol. 50, part 11, gives a figure (Tab. 34, fig. 15) of some specimens from the West Indies, which I believe to be B. perforatus: hence, it is in some degree probable that this species, like B. tintinnabulum, and amphitrite, and improvisus, may be found on both sides of the equatorial Atlantic. Balanus perforatus is attached, together with B. tulipiformis, trigonus, amphitrite, Chthamalus stellatus, and Pollicipes cornucopia, usually to rocks, near the lower limit of the tidal level; but I believe, from specimens kindly sent me by Mr. Mac Andrew, that it is frequently obtained by dredging; one specimen was even marked 30 fathoms. According to Poli, it is sometimes attached to the bottoms of vessels; and I have seen a specimen adhering to the floating Lepas Hillii.

Affinities. — This is a distinct species, closely allied to no other species, but comes nearest to B. lævis, which is its representative in Southern America, and on the whole west coast of that continent. It is allied to that species, and differs from most other species, in the general form of the shell, its small orifice, narrow radii, and often deeply cup-formed basis. It agrees to a certain extent in the colouring, though the purple here is much more prevalent, and is not confined to the shelly matter filling up the parietal tubes. It agrees with that species in the general structure of the scutum; but the two or three deep, longitudinal furrows are here absent; and the minute ridge, parallel to and almost under the adductor ridge, is a peculiarity confined to this and very few species in the genus. The terga differ from those of B. lævis, chiefly in the spur being narrower, and in the apex being beaked. Lastly, the highly protuberant segments of the one ramus in the first cirrus, and of both rami in the second pair, are here remarkable. With regard to the varieties, I have nothing to add to their short diagnostic characters above given.

 

18. BALANUS CONCAVUS. Pl. 4, fig. 4 a-4 e.

BALANUS CONCAVUS. Bronn. Italiens Tertiär-Gebilde (1831) et Lethæa Geognostica, b. ii, s. 1155 (1838), Tab. 36, fig. 12.

  ——  — CYLINDRACEUS, var. c. Lamarck. Animaux sans Vertèbres (1818).

LEPAS TINTINNABULUM. Brocchi. Conchologia Sub-Appen., t. ii,  (1814).

I suspect that B. pustularis, miser, and zonarius, all figured by Münster, in his ‘Beiträge,’ b. iii, Tab. 6, may be this species.

Shell longitudinally striped with white and pink; or dull purple; sometimes wholly white. Scutum finely striated longitudinally; internally, adductor ridge very or moderately prominent.

Hab. — Panama; Peru; S. Pedro in California; Philippine Archipelago; Australia. Mus. Brit., Cuming, Stutchbury, Aug. Gould.

Fossil in Coralline Crag, England; Mus. Brit., S. Wood, Bowerbank, Lyell, J. de C. Sowerby, Tennant. Sub-Appennine formations, near Turin, Asti, Colle in Tuscany, Mus. Greenough, &c. Tertiary beds, near Lisbon, Mus. D. Sharpe and Smith. Bordeaux (?) Mus. Lyell. Tertiary beds, Williamsburg; and Evergreen, Virginia, Mus. Lyell. Maryland, Mus. Krantz. Recent formations near Callao, Peru, Mus. Darwin. Red Crag (Sutton) Mus. S. Wood.

I procured this specimen from the Island of S. Lorenzo, off Callao; it was imbedded, together with seventeen species of recent shells and with human remains, at the height of eighty-five feet.

This species has caused me much trouble. Looking first to the recent specimens, I examined several from Panama and California, which, though differing greatly in colour, resembled each other in their scuta having the adductor ridge extremely prominent, and in having (Pl. 4, fig. 4 a), an almost tubular cavity for the attachment of the lateral depressor muscle, — characters which at first appeared of high specific value; but I soon found other specimens from Panama in which these peculiarities were barely developed. I then examined a single specimen from the Philippine Archipelago, resembling in external appearance one of the Panama varieties, but differing in the scuta being externally strongly denticulated in lines instead of being merely striated, — in the adductor ridge being far less prominent, — and in the spur of the tergum being broader and more truncated; I therefore considered this as a distinct species. I then examined a single white rugged specimen from the coast of Peru, which differed from the Philippine specimen in the shape of the well-defined denticulations on the scuta, and in some other trifling respects, and in the segments of the posterior cirri bearing a greater number of spines; with considerable doubt, I also named this as distinct. But when I came to examine a large series of fossil specimens from the Coralline Crag of England, from northern Italy, from Portugal, and from the southern United States, I at once discovered that the form of the denticuli on the scuta was a quite worthless character, — that in young specimens the scuta were only striated, — that the prominence of the adductor scutorum ridge and the depth of the cavity for the lateral depressor muscle varied much (as in the case of the recent specimens), owing apparently to the varying thickness of the valve, — that in the terga the spur varied considerably in length and breadth, the latter character being in part determined by the varying extent to which the edges of the longitudinal furrow are folded in, — and lastly, that in young specimens the basal end of the spur is much more abruptly truncated than in the old. Hence I have been compelled to throw all these forms, originally considered by me as specifically distinct, into one species. I must repeat that this considerable variation in the prominence of the adductor ridge, and in the depth of the pit for the lateral depressor muscle — the pit in some cases becoming even tubular — is a very unusual circumstance.

 

With respect to the fossil specimens from the above-stated several distant localities, I consider them as certainly belonging to one species, though varying considerably in several points of structure. When compared with the recent specimens, they differ from them in often attaining a considerably larger size; in the parietes being often, but not always, longitudinally ribbed; and in the radii often having more oblique summits. On the other hand, considering the many points of identity between the fossil and the recent specimen, I have concluded, without much doubt, that they ought all to be classed together. I may remark that, in the Coralline Crag specimens, the spur of the tergum (Pl. 4, fig. 4 d), is unusually long and narrow; it is broader and shorter in the Italian specimens (4 e), and variable in this respect, in the United States specimens; the scuta of the Lisbon specimens are remarkable for the greater prominence of the adductor ridge, and for the depth of the lateral depressor cavity. Some of the specimens from all the several localities are identical with the recent ones from the coast of Peru. The walls of the shell in the Coralline Crag specimens, are generally ribbed longitudinally. I have entered into the above particulars, on account of, in the first place, its offering an excellent example how hopeless it is in most cases to make out the species of this difficult genus without a large series of specimens; secondly, as showing how the characters alter with age; and thirdly, as a good instance of the amount of variation which seems especially to occur in most of the species which have very extensive ranges.

These will be fully illustrated in the monograph on the Fossil Balanidæ, to be published by the Palæontographical Society.

Some of the pink-striped Panama varieties, though having a somewhat different aspect, can be distinguished from certain varieties of B. amphitrite only by their scuta being longitudinally striated, — a character in this species variable in degree, and in most cases of very little value. Some of the other recent varieties are sufficiently distinct from B. amphitrite; and the great fossil Coralline Crag specimens, which stand at the opposite end of the series of varieties, with their ribbed walls, very oblique radii, and coarsely striated scuta, are extremely unlike B. amphitrite. With respect to the nomenclature of the present species, I have little doubt that I have properly identified the Italian fossil specimens with B. concavus of Bronn, who has given a very good figure of this species in his ‘Lethæa Geognostica;’ it must, however, be confessed that the longitudinal striæ on the scuta are not there represented. Considering the large size and frequency of this species in Europe and in the United States, it has probably received several other names, besides the two incorrect synonyms, quoted at the head of this description. I should add that the true B. cylindraceus (not var. C) of Lamarck, according to the plate given by Chenu in his ‘Illust. Conch.,’ is the B. psittacus of South America. I have seen in collections specimens of B. concavus labelled as B. tulipa of Poli (B. tulipiformis of this work), — a very natural mistake, without the opercular valves be carefully examined.

General Appearance. — Shell conical, often steeply conical; orifice rather small, with the radii narrow, and generally in the fossil specimens very oblique; surface generally smooth, sometimes rugged, and in the coralline crag specimens generally ribbed longitudinally, the ribs being narrow. Colour various, either dull reddish-purple with narrow nearly white, or wider dark longitudinal bands; or, again, pale rosy-pink with broad white bands; or lastly, wholly white. The radii are either darker or paler than the parietes. The opercular valves are either dark purple or nearly white. Pale pink and white stripes are visible on some of the Italian and Portuguese tertiary specimens; and in most of the fossils the sheath is tinged dull red.

Dimensions. — The largest actually recent specimen which I have seen, from the Philippine Archipelago, had a basal diameter of 1.2 of an inch; the Peruvian pleistocene specimen is 1.7 in diameter; specimens from the crag and from the Italian deposits, however, sometimes slightly exceed two inches in basal diameter, and three in height.

Scuta: these in young and moderately-sized specimens are striated, sometimes very faintly, but generally plainly, causing the lines of growth to be beaded; but often, in large and half-grown specimens, the lines of growth are extremely prominent, and being intersected by the radiating striæ, are converted into little teeth. As the striæ often run in pairs, the little teeth frequently stand in pairs, or broader teeth have a little notch on their summits, bearing a minute tuft of spines. In very old and large specimens, the prominent lines of growth are generally simply intersected by deep and narrow radiating striæ. In one case, a single zone of growth in one valve was quite smooth, whilst the zones above and below were denticulated. The valve varies in thickness, which I think influences the prominence of the lines of growth and the depth of the striæ. These striæ often affect the internal surface of the basal margin, making it bluntly toothed. The articular ridge is rather small, and moderately reflexed: the adductor ridge (as already stated,) varies remarkably; in most of the Panama specimens, it is extremely prominent, and extends down to near the basal margin; in other specimens it is but slightly prominent, especially in some of the fossil specimens from Virginia. The cavity for the lateral depressor, also, varies greatly; it is often bounded on the side towards the occludent margin by a very slight straight ridge, which occasionally folds a little over, making almost a tube; this, at first, I thought an excellent specific character, but far from this being the case, the cavity often becomes wide, quite open, and shallow.

Terga, very slightly beaked; the surface towards the carinal end of the valve, in some of the fossil specimens, is very slightly striated longitudinally. There is either a slight depression, or more commonly a deep longitudinal furrow, with the edges folded in and touching each other, extending down the valve to the spur, and causing the latter to vary in width relatively to its length. When the furrow is closed in, the spur is about one fourth of the entire width of the valve, and has its lower end obliquely rounded, and stands at about its own width from the basi-scutal angle: when there is only a slight depression and no furrow (as is always the case with young specimens), the spur is broader, equalling one third of the width of the valve, with its lower end almost truncated, and standing at about half its own width from the basi-scutal angle. But the absolute length of the spur, also, varies considerably; it is often very long, compared to the whole valve. The basal margin on the carinal side is sometimes slightly hollowed out; when the furrow is closed, this latter side slopes towards the spur. Internally, the articular ridge and crests for the tergal depressor muscle are moderately prominent.

Parietes, the longitudinal septa sometimes stand near each other, making the parietal pores small. The radii have oblique summits, but to a variable degree; their septa are unusually fine, and are denticulated on their lower sides; the interspaces are filled up solidly. The alæ have their summits very oblique, with their sutural edges nearly or quite smooth. In most of the fossil specimens, and slightly in some of the recent specimens, the surface of the sheath presents an unusual character, in a narrow, longitudinal, slightly raised border, running along the sutures, on the carinal side of each compartment.

Basis thin, porose; sometimes with an underlaying cancellated layer.

Mouth: labrum with six teeth: mandibles with the fourth and fifth teeth small, either sharp, or blunt: maxillæ with a straight edge, or with the inferior part slightly prominent. Cirri with the rami of the first pair unequal by four or five segments: the segments in the shorter ramus are extremely protuberant. The segments in the second cirrus only moderately protuberant: but all the specimens were in bad condition, and it appeared as if, in the Panama specimens, the segments of the second cirrus were more protuberant than in the Philippine Island specimens. In the posterior cirri there are from three to five pairs of spines on each segment: even amongst the Panama specimens some had three and some four pairs, and a white Panama specimen had five pairs of spines.

 

All the recent specimens which I have seen, were, with one exception, attached to various shells and crabs, and to each other. The Peruvian specimen was associated with B. flosculus. The tertiary specimens are often congregated together into great masses. Including the recent and fossil specimens, this species encircles the globe. During the miocene period it seems to have been the commonest existing sessile cirripede; now, it does not appear to be common, excepting, perhaps, at Panama: Mr. Cuming procured only one specimen from the Philippine archipelago.

 

19. BALANUS AMPHITRITE. Pl. 5, fig. 2 a-2 o.

LEPAS RADIATA. Wood’s General Conchology (1815), Pl. 7, fig. 7.

  —— MINOR? Wood’s General Conchology (1815), Pl. 7, fig. 6.

  —— BALANOIDES. Poli. Testacea utriusque Siciliæ (1795), Tab. 5.

BALANUS BALANOIDES. Risso. Hist. Nat. de l’Europe Merid., tom. iv, 1826.

Shell longitudinally striped with purple or pink; sometimes with the stripes confluent; sometimes wholly white. Scutum internally with a prominent broad adductor ridge.

Var. (1) communis: (2 e, 2 h, 2 l,) nearly white, with pale or dark violet-coloured longitudinal stripes: epidermis rarely persistent: shell either thin or thick: radii white or freckled with reddish mahogany colour, with their summits either oblique, sometimes in a high degree, or nearly parallel to the basis: basal point of spur of the tergum either square or bluntly pointed. Hab. Mediterranean, W. Indies, S. Africa, Philippine Archipelago, New South Wales.

Var. (2) venustus: (2 a,) white or pale pink, with narrow bright pink, or broad pinkish-purple stripes; orifice either much dentated or nearly entire. Tergum with the carinal half of the basal margin sometimes much hollowed out. Hab. W. and S. Africa, Ceylon.

Var. (3) pallidus: (2 c, 2 k,) white, with or without a yellowish persistent epidermis; sometimes with the edges of the compartments tinted purple: radii moderately oblique: tergum generally narrow, with the spur sharp, and the basal margin on its carinal side much hollowed out. Hab. W. Africa, Madagascar, Red Sea.

Var. (4) niveus: (2 f,) white, with longitudinal hyaline lines; epidermis not persistent. Hab. W. Indies, Florida, S. Africa, &c.

Var. (5) modestus: upper part of shell white, lower part uniform blueish-gray, opercular valves as in Var. (1). Hab. unknown.

Var. (6) Stutsburi: (2 d, 2 i, 2 m, 2 n, 2 o,) white, with or without pinkish-purple stripes, which are often confluent, rendering the lower part of the shell of a uniform purplish tint; epidermis persistent: radii very narrow: tergum narrow, spur sharp, varying in form and in exact position; carinal margin sometimes highly protuberant; basal margin on the carinal side of the spur generally, but not invariably, much hollowed out. Hab. West Africa.

Var. (7) obscurus: (Pl. 5, fig. 2 g,) with narrow, approximate, obscure and often almost confluent, slaty, or pale purplish-brown, or dark slate-coloured stripes. Hab. West Indies, Australia, and unknown.

Var. (8) variegatus: with narrow, approximate, dusky, claret-coloured stripes, transversely freckled with white; shell conical; walls very thin: scutum with the adductor ridge small. Hab. New Zealand.

Var. (9) (an. spec.?) cirratus: (fig. 2 b,) shell very pale purplish-brown, with faint, more or less plain longitudinal stripes, transversely freckled with white; walls thin: scuta with the lines of growth beaded: basis, in specimens growing in groups, irregularly cup formed: maxillæ with the inferior corner extremely prominent. Hab. Mouth of Indus, Australia, Philippine Archipelago.

Hab. — Warmer temperate and tropical seas; extremely common; Mediterranean, Smyrna, Sicily, Coast of Portugal; West Coast of Africa, River Gambia, West Indies, Demerara, Natal, Madagascar, Red Sea, Mouth of the Indus, Ceylon, Philippine Archipelago, East Indian Archipelago, Pacific Ocean, east coast of Australia, New Zealand; extremely common on ships’ bottoms; often attached to floating timber, canes, &c.; often associated with B. tintinnabulum; attached to pebbles and various shells.

With respect to the nomenclature of this extremely common species, which is widely distributed in all the warmer seas (excepting, as far as I have seen, on the west coast of America), there is some difficulty. I have no doubt that it is the Lepas radiata of Wood (1815), but Bruguière, in 1789, gave this same name to a Balanus which he had not seen, but which is figured in Chemnitz, Tab. 59, fig. 842. I should have thought that this also had been the present species, but Spengler, in describing (Skrifter af Naturhist. Selskabet i, B. 1790) this individual specimen, which he calls L. purpurea, states that it is 13 lines in basal diameter; now this is a size which is never acquired by B. amphitrite; and the description, habits, and size, would apply equally well to the species which I have called B. amaryllis; but when no notice is taken of such points of importance, as whether the walls are permeated by pores, whether the radii are smooth-edged, whether the scuta are striated, it is impossible to identify with any approach to certainty sessile Cirripedes; and the names given ought, in my opinion, to carry little weight with them. With respect to Lamarck’s Balanus radiatus (1818), the synonyms quoted exhibit some great and inextricable confusion. The B. radiatus, again, of Risso, is a fossil and apparently distinct species. There can be no doubt that the present species is the Lepas balanoides of Poli, (and of several authors who have followed him), and equally little doubt that the present species is not the true L. balanoides of Linnæus, which has a membranous basis, and which I have not seen from the Mediterranean. Under these circumstances I have concluded that less confusion would be caused by giving a new name to this species than by taking that of Wood, which ought not to have been used by him, considering Bruguière’s previous adoption of it.

Under the head of B. tintinnabulum I have alluded to the great variation of B. amphitrite, which consists not only in a vast diversity in the colouring and in the general aspect, but likewise in the degree of obliquity of the summits of the radii, in the form of the terga, and slightly in that of the scuta. In order to show that it has not been from indolence that I have put so many forms together, I may state that I had already named and fully described in detail eight of the following forms as species, when I became finally convinced that they were only varieties: it would require at least thirty figures, which I have not the power to give, fully to illustrate the transitional forms. As with B. tintinnabulum, the deception is wonderfully enhanced by whole groups of specimens from the same locality exactly resembling each other, and sometimes differing from other groups attached to the very same object. If a person were to get together only some fifty or sixty specimens from only half a dozen different localities, he would almost certainly come to the same conclusion, as I at first did, that several of the varieties are true species; but when he gets several hundred specimens from all quarters of the globe, he will find, to his trouble and vexation, that character after character fails and blends away by insensible degrees, and he will be led, as the more prudent course, to include, as I have done, and I hope rightly, all under one specific name. I have experienced more doubt regarding the last variety, cirratus, than on any other, on account of its peculiar colouring, and from the basis being often irregularly cup-formed. Under B. concavus I have remarked how closely some of its varieties approach to B. amphitrite, and it is to this last variety that they approach; almost the only difference being that the scuta in B. concavus are longitudinally striated. Yet some of the varieties of the two species are so distinct that it would be puerile to class them together. I will only add, that after studying such varying forms as B. tintinnabulum and amphitrite it is difficult to avoid, in utter despair, doubting whether there be such a thing as a distinct species, or at least more than half a dozen distinct species, in the whole genus Balanus.

As with B. tintinnabulum, I will first give a full description of the more common forms, alluding only to each less frequent variation, and then separately describe briefly the more marked varieties.

General Appearance. — Shape conical, either steep or considerably depressed; sometimes tubular; orifice either nearly entire or deeply toothed, not large, varying from rhomboidal to rounded-trigonal. Surface of shell smooth, never ribbed, generally naked, but occasionally the yellowish epidermis is persistent; in the same individual, I have seen all the lower part of the shell thus covered and the upper part naked, the line of separation being defined. The colour varies much, even sometimes considerably on the same individual; generally white or pale gray, with dull violet-coloured, longitudinal, moderately broad stripes; these stripes are sometimes equidistant, but more usually they are arranged so as to leave broad white spaces; the stripes fade away by endless variations, the edges of the compartments and the carinal end of the shell longest retaining any colour, until we have a uniformly white shell, generally covered with a yellowish epidermis; or the white is longitudinally marked with hyaline lines; this latter variety has a very peculiar aspect, and I did not doubt it was specifically distinct, until, in a number of specimens on a ship from the West Indies, I got the most perfect series, and another scarcely less perfect series from the Mediterranean, graduating into common coloured varieties. Rarely the dull violet or purple stripes become approximate and dark, so that the whole shell is tinted of a brownish slate-colour, occasionally freckled with white. Again, we have another set of very pretty varieties, with a white or very pale pink ground, with either narrow bright pink or broad pinkish-purple stripes. Again, I have seen numerous specimens of a variety, var. Stutsburi, from the west coast of Africa, in which the upper part of the shell is white, and the lower part shaded with pinkish or dark purple approximate stripes, which often become confluent; in one group, the whole shell being thus uniformly coloured, without any vestige of stripes. I have seen another group from an unknown locality, in which the lower part of the shell was uniformly blueish-gray. A variety from Australia has narrow approximate dark claret-coloured stripes, transversely freckled with white. Lastly, in the variety cirratus, the whole shell is very pale purplish-brown, with indistinct longitudinal brownish stripes, transversely freckled with white lines. I considered this as a distinct species, until quite lately finding forms which I could not possibly determine whether to class as B. cirratus or amphitrite.

The radii are generally snow-white, or freckled with a bright mahogany tint, or rarely clouded with purple, or in the pink varieties with pink. The scuta are dull purple or pink, generally with a white band along their tergal margin; often, however, they are white, with merely one or two purple fasciæ. The thickness or strength of the shells varies much; some specimens attached to a floating cane, from Natal and the Philippine Archipelago, were extremely strong; others, from the Mediterranean and Australia, and some tubular varieties from the West Indies, were very thin, translucent, and fragile. Size: large specimens generally attain a diameter of from half to three quarters of an inch in basal diameter; and I have seen one or two specimens an inch in diameter.

Scutum; sometimes the surface is very smooth, but generally the growth-ridges are moderately prominent; the latter are occasionally very finely beaded, and this seems always the case with var. cirratus. Internally, the articular ridge is prominent and reflexed: the adductor ridge is sharp, very prominent, and straight; it runs parallel to the occludent margin; close to its lower side there is often a depression (Pl. 5, fig. 2 i), sometimes bounded by a slight ridge, as if for the attachment of a muscle, but there certainly is no muscle here: rarely the adductor ridge is only slightly prominent: there is a small and shallow little pit of variable depth for the lateral depressor muscle.

Tergum (2 k-2 o); this valve is here far more variable than in any other species: in the commonest purple-striped forms (2 l), the valve is rather broad, the basal margin lies in nearly a straight line on the opposite sides of the spur, which is placed at rather less than its own width from the basi-scutal angle; the spur is rather short, and in width about one fourth of the entire valve; its lower end is either bluntly pointed or more commonly nearly square (2 k) and parallel to the basal margin: in young specimens it is generally sharper than in older ones. Externally, in the line of the spur, there is either a slight longitudinal depression, or more rarely a deep furrow. The carinal margin is more or less convex, and is formed by upturned lines of growth: the scutal margin is broadly inflected. Internally, the articular ridge in the upper part is very prominent: the crests for the tergal depressor muscle are moderately prominent, but very variable. Sometimes the carinal portion of the basal margin is slightly hollowed out. In var. Stutsburi (2 m, 2 n, 2 o), and in some white varieties, which differ most in the shape of the tergum from the commoner varieties, the whole valve is narrower, the spur is much sharper and narrower, the carinal half of the basal margin is much hollowed out and slopes down towards the spur, with the crests for the depressor muscles depending beneath the basal margin, and with the carinal margin sometimes extremely convex or protuberant. But the shape and position of the spur, and the outline of the carinal half of the basal margin vary much in nearly all the varieties.

Compartments. — The upper parts of the parietal pores are either filled up solidly with, generally coloured, shell, or they are crossed by thin transverse calcerous septa: the longitudinal parietal septa occasionally bifurcate at their bases close to the outer lamina, making an irregular outer row of minute pores. The Radii have their septa rather fine, and finely denticulated on both sides, but sometimes only on the lower side; the thickness of the septa varies a little; the interspaces are filled up solidly; the summits of the radii are jagged and oblique, and usually form an angle of about 45° with the basis, not being added to above the level of the opercular membrane; but not rarely they reach up much higher, and are very nearly parallel to the basis, extending from tip to tip of the compartments. Again, in some ordinary varieties, and always in var. Stutsburi, the summits of the radii are extremely oblique, the radii themselves forming a mere border to the compartments to which they belong. In no other species have I seen so great an amount of variation in the form of the summits of the radii. The alæ, in like manner, have their summits either very oblique, not being added to above the opercular membrane, or they are only slightly oblique; it often happens that in those specimens in which the summits of the radii are nearly parallel to the basis, the alæ are very oblique, and the converse: in other individuals, both radii and alæ have equally oblique summits. The sutural edges of the alæ vary in thickness, being either very thin and obscurely crenated, or moderately thick and ribbed. The basis is porose; but I have never seen an underlying cancellated layer of shell, as is so common in several species.

Mouth: labrum, with from four to eight, generally with six, little teeth: mandibles with three teeth, and two minute lower teeth, or mere knobs: maxillæ with the edge straight, or with the inferior part forming a slightly step-formed projection. Cirri: the rami of the first pair are unequal by three or four segments, but in some specimens by five or six segments, with the front surfaces of the segments in the shorter ramus extremely protuberant. The second pair of cirri are short, with the front surfaces of the segments moderately protuberant: the third pair have a tuft of bristles at their bases on the thorax. The segments in the sixth pair have from four to six pairs of spines on the segments; equal-sized specimens seem to vary in this latter respect. There is a small sharp projection on the dorsal base of the penis.

Varieties.

With respect to var. 1, communis, I have nothing further to remark, except that I have seen specimens identically similar from the Mediterranean, Natal, the Philippine Archipelago, and Sydney; at the latter place it is said to be rare, but in most places it is the commonest variety, and is often attached to ships’ bottoms. Of var. 2, venustus, I have seen specimens from the west coast of Africa, Natal, and Ceylon, in groups by themselves, and associated with var. communis; it is much less common than var. 1. The third variety, pallidus, is not uncommon; I have seen many specimens from the bottoms of ships, from the West Indies, and the west coast of Africa. Of the var. 4, niveus, I have seen the most perfect graduated series passing into var. 1, both from the West Indies, Florida, and the Mediterranean: I have seen other specimens from the Red Sea and Madagascar. Of the var. 5, modestus, I have seen only one group from an unknown locality; it is only remarkable from its uniform colouring. The var. 6, Stutsburi, is more remarkable than the foregoing; until quite lately I did not doubt that it was specifically distinct; but as I have seen every character graduate into other varieties, I am now convinced that it is not a true species: all the specimens which I have seen have come on shells, or on ships’ bottoms, from West Africa. Of var. 7, obscurus, I have seen three or four groups of specimens from unknown quarters, both on pebbles, shells, and on cork (probably from the Atlantic ocean); and likewise some specimens taken from the bottom of Her Majesty’s ship “Fly,” on the east coast of Australia; these latter are intermediate in character with the next var. variegatus; from the Australian seas, which I at first ranked as an undoubted species, but I have subsequently failed in discovering any sufficient diagnostic character. Lastly, of var. cirratus, I have seen several groups of specimens from India and the Philippine Archipelago, and a group intermediate in character between this and the first and third varieties, from Australia; I retained this variety owing to its peculiar freckled, pale brown colouring and beaded scuta (of which, however, I have seen decided traces in the common variety), as a distinct species, after I had given up all the foregoing forms. I entertain some doubts whether I have now acted right; but when I found some specimens which, I found it impossible to decide, whether to rank as amphitrite or cirratus, I determined to take the more prudent course, and sink the latter as a species. This variety, also, seems to connect B. amphitrite and concavus very closely.

 

20. BALANUS PŒCILUS. Pl. 5, fig. 3 a, 3 b.

Shell dull red, freckled with white. Scutum internally without an adductor ridge; tergum with the spur, sharply truncated, almost one third of width of valve.

Hab. — West coast of South America, Mus. Cuming; attached to an Avicula.

The appearance of the fragile shell, in the one group of specimens which I have seen, leads me to suspect that they may have grown under unfavorable circumstances. This species differs considerably in general aspect, but not much in essential characters, from B. amphitrite; the absence, however, of an adductor ridge to the scutum, and the sharply truncated spur of the tergum, are sufficient to distinguish them. In the opercular valves this species comes near to B. vinaceus, also from the west coast of South America; but the striated scuta of that species, the cancellated inner lamina of the parietes, the general colouring, and square porose radii, are amply diagnostic characters.

General Appearance. — Shell fragile, tubulo-conical, orifice large, passing from diamond-shaped into oval. Colour fine dark rose, freckled with transverse, sharply pointed, fine zig-zag white lines: the pink is also so arranged as to obscurely give to the walls a longitudinally striped appearance: radii generally rather whiter than the walls, and similarly freckled: terga similarly freckled: scuta dull red, with a white band along the scutal margin. Basal diameter of largest specimen half an inch.

Scutum, externally smooth: internally, articular ridge moderately developed, slightly reflexed: there is no adductor ridge: there is a distinct pit for the lateral depressor muscle. Tergum, with the scutal margin unusually prominent, toothed: longitudinal furrow shallow, the edges apparently having no tendency to fold in: spur short, barely one third of width of valve, with the lower end sharply truncated, parallel to the basal margin: articular ridge and crests for the depressores moderately prominent.

Compartments. — Walls very fragile, with the outer lamina not thicker than the inner lamina. Radii fragile, broad, with their summits moderately oblique; their sutural edges have the septa plainly denticulated on both sides, with the interspaces filled up solidly nearly to the tips of the septa. Alæ, with their summits more oblique than those of the radii; their sutural edges smooth. Basis with an underlying cancellated layer. Mouth: labrum with three unusually large teeth on each side of the notch: mandibles with the fourth tooth tolerably well developed, the fifth being confluent with the inferior angle. Maxillæ simple. Cirri, — first pair with one ramus longer by about four segments than the other ramus, which has considerably protuberant segments: second pair with segments only moderately protuberant: sixth pair with segments much elongated, but bearing only four pairs of spines.

 

 

21. BALANUS EBURNEUS. Pl. 5, fig. 4 a-4 d.

BALANUS EBURNEUS. Aug. Gould (!). Report on the Invertebrata of Massachussetts, 1841, fig. 6.

Shell yellowish white. Scutum striated longitudinally: tergum with the spur truncated, the basi-carinal margin generally much hollowed out, and the carinal margin protuberant in the upper part.

Hab. — United States, from about lat. 42° to Charlestown; West Indies; Honduras; Venezuela; attached to shells and floating wood. Attached to ships’ bottoms from Trinidad and Jamaica, associated with B. tintinnabulum, amphitrite, and improvisus. Brackish water, Salem, Massachussetts, according to Mr. Stimpson. Mus. Aug. Gould, Agassiz, Stutchbury, Cuming, W. Dunker, &c.; very common.

General Appearance. — Shell conical, or almost tubular; white, with the surface very smooth, covered by thin yellowish epidermis, but with the radii naked. Orifice large, passing from rhomboidal into pentagonal, moderately toothed. Average full size, about one inch in basal diameter; I have seen a specimen 1.3 in basal diameter, and the same in height.

Scutum, plainly striated longitudinally: the teeth on the occludent margin small. Internally, the upper surface is roughened: the articular ridge is prominent, and either slightly or not at all reflexed: the pit for the adductor muscle is distinct; the adductor ridge is prominent in a variable degree, and is almost confluent with the articular ridge. In one specimen from Beverly Bay, U. S., the scuta were extraordinarily disintegrated, and I could perceive no trace of the external radiating striæ. Tergum, with the basal margin on the carinal side of the spur sometimes deeply (Pl. 5, fig. 4 b), and sometimes only slightly (fig. 4 d), and rarely hardly at all, hollowed out: when much hollowed out the valve may almost be said to be two-pronged, with the carinal prong narrower than the spur. There is no distinct longitudinal furrow, but the whole scutal margin projects above the general surface of the valve. In the carinal margin, in the upper part, there is a remarkable convexity or protuberance in the same plane with the valve, from which it is separated by a very slight and narrow ridge. The spur is about one fourth of the width of the valve, with its lower end abruptly truncated. Internally, the upper surface is much roughened with finely crenated ridges: the distinct crests for the depressores cover the whole of the so-called carinal prong.

Compartments; the radii and alæ have their summits oblique, sometimes a little rounded, but not smooth. The septa on the sutural edges of the radii are remarkably fine, and closely approximate; the denticuli are excessively minute. The sutural edges of the alæ are most delicately crenated; the alæ are largely added to during the diametric growth of the shell, and above the level of the opercular membrane. The parietal pores are square and rather large: they are crossed by transverse septa almost close down to the basis: the longitudinal septa have tolerably large denticuli at their bases. The pores in the basis are crossed by numerous transverse septa. When specimens grow in a group, the basis is sometimes irregularly cup-formed.

Mouth: labrum serrated with small teeth, decreasing in size downwards, on each side of the central notch. Mandibles with the third tooth rather thick and blunt, and with the fourth and fifth knob-like. Maxillæ, with the inferior part projecting much beyond the rest of the edge, and bearing two long single spines: between these two spines and the large upper pair, there are, in a full-sized specimen, about seven pairs of moderately long spines, feathered on their sides. Outer maxillæ thickly clothed with very fine spines, and remarkably prominent.

Cirri: first cirrus, with one ramus having twenty-six segments, and longer by ten segments than the shorter ramus, which has sixteen segments: the shorter ramus, and both ramii of the second pair, have their segments remarkably protuberant in front; the protuberance, in the upper segments, equalling in length the supporting part of each segment: rami of the second cirrus unequal in length by five segments. Third cirrus with the segments only slightly protuberant; rami considerably longer than those of the second cirrus: at the dorsal base of the pedicel of this third cirrus there is no tuft of fine hairs, as is common in many other species. Sixth pair, with the upper segments elongated, bearing from six to seven pairs of spines; dorsal spines short, thin, and few.

Affinities: in external appearance of the shell, this species can hardly be distinguished from some of the white varieties of B. amphitrite; and there is a considerable resemblance, in some of the varieties, in the opercular valves; but the longitudinally striated scuta of B. eburneus suffice to distinguish these certainly very distinct species. Equally, or even more like externally, is this species to the B. Hameri, so that I have received from an eminent naturalist in the United States both species mingled in the same lot, all bearing the same name of B. eburneus; but when the internal structure of the shell is examined, the species are at once seen to be far removed from each other. Still more close is the affinity of this species to B. improvisus, both in internal and external characters: it agrees with this species in the singular habit of being able to live in brackish water: these two species are the only ones which have the labrum serrated with teeth, graduated in size, on each side of the central notch. In the case of young specimens of the var. assimilis of B. improvisus, an inhabitant of the same seas with B. eburneus, the diagnosis is most difficult without long practice; for in the young of eburneus, the compartments are only partially covered by yellow epidermis, and have a striped appearance, the radii are sometimes very oblique, the scuta externally have not acquired their longitudinal striæ, and internally the adductor ridge lies not so close to the articular ridge as it does subsequently; hence I for some time mistook the var. assimilis of B. improvisus for the young of B. eburneus. But I found in the latter, that the rami of the first pair of cirri, are always, even in the earliest youth, more unequal in length, and that each segment of the posterior cirri bears a greater number of pairs of spines, there being, even in very minute specimens, seven pairs. Moreover, after having examined scores of specimens, I found I could almost always distinguish the two species by the smoothness and curvature of the summits of the radii of B. improvisus; I entertain no doubt whatever about the distinctness of the two species; indeed, when both are mature, besides the greater size, striated scuta, &c. of B. eburneus, their general aspect is very different.

 

22. BALANUS IMPROVISUS. Pl. 6, fig. 1 a-1 c.

Shell white: radii narrow, with their upper margins smooth, slightly arched, very oblique. Tergum with a longitudinal furrow; spur with the end rounded.

Var. assimilis, with longitudinal white hyaline lines.

Hab. — England, Scotland, Belgium (?), Nova Scotia, United States, West Indies, Rio Plata, Southern Patagonia, Guayaquil, West Colombia; attached to wood, shells, rocks, ships’ bottoms, from low tidal level to twenty fathoms depth.

General Appearance. — Shell conical, with a rather large diamond-shaped orifice, moderately or but little toothed; very smooth; walls never folded longitudinally; white, with an extremely thin pale-yellow persistent epidermis. The radii are very narrow, with their summits very oblique, rounded, and smooth; the epidermis is generally more persistent on the radii than on other parts, and this is exactly the reverse of what is common with B. eburneus. The specimens from nearly fresh-water in the R. Plata (hereafter to be mentioned), are brownish, and have undergone a remarkable degree of corrosion, the outer lamina of the walls having been entirely removed to near the base; hence the external aspect of these specimens is wholly different from ordinary individuals. The var. assimilis has also a very different appearance, owing to the dead white of the walls being relieved by narrow approximate longitudinal hyaline lines, corresponding with and caused by the longitudinal parietal septa being externally visible through the outer lamina of the parietes; the epidermis on the radii is also of a rather brighter yellow. The largest specimens which I have seen are those from the Plata, and those attached to a ship from the West Indies, and they had a basal diameter of .6 of an inch: from .4 to .5 of an inch is the more usual full average size.

Scuta, with the lines of growth but little prominent: articular ridge prominent, but little reflexed: adductor ridge straight and very prominent, varying a little in its distance from the articular ridge; there is scarcely any depression for the lateral depressor muscle; the upper internal surface of the valve is roughened with ridges. Terga, with a moderately deep longitudinal furrow; spur short, rather narrow, with the end rounded, placed at less than its own width from the basi-scutal angle; in the Rio Plata specimens the spur is close to this angle: the basal margin is generally straight on opposite sides of the spur, but sometimes on the carinal side it is a little hollowed out. The lines of growth are upturned along the carinal margin, which consequently is a little protuberant, but to a varying degree. The crests for the depressores are extremely distinct and prominent. In the varieties having the basi-carinal margin hollowed out, and the carinal margin protuberant, there is a marked resemblance to the peculiar tergum of B. eburneus.

Walls: the parietal pores are tolerably large, and are crossed by numerous transverse septa: the longitudinal septa are very finely denticulated at their bases, but occasionally almost smooth. The radii are, as stated, extremely narrow, and very remarkable from their smooth rounded edges; their septa are barely denticulated. The alæ are remarkably protuberant; they have their summits much less oblique than those of the radii, and sometimes they are almost parallel to the basis: their sutural edges are coarsely crenated. Basis, flat, thin, permeated by pores, but the pores do not generally run to the very centre; they are, as usual, crossed by transverse septa.

Mouth: the labrum is the most remarkable part; on each side of the central notch there are generally two teeth; and on the two sides of the notch itself nine or eleven smaller teeth, decreasing regularly in size downwards till they become so minute as to be hardly visible even under the compound microscope; thus, in the two specimens closely examined, there were altogether twenty-two and twenty-six teeth on the labrum. Mandibles with the two inferior teeth reduced to mere knobs: maxillæ with the lower part of the edge bearing two large spines, and generally, but not always, forming a step-formed projection. Cirri: the ramii of the first pair are but slightly unequal; in one specimen examined there were fifteen segments in one ramus and twelve in the other: segments very protuberant in front. Second cirrus with the segments only slightly protuberant; segments thirteen. Third cirrus longer than the second pair, with the rami rather unequal in length: there is a tuft of long spines on the basal segment of the pedicel of this cirrus. Fourth cirrus twenty-two segments. Sixth cirrus, in the same individual, thirty-four segments: on each of these segments there are five or six pairs of spines. I may specify that the longer ramus of the first cirrus of a large Rio Plata specimen had twenty-four segments.

Varieties, affinities. — When I first met with the var. assimilis, misguided by its general aspect, I did not doubt that it was specifically distinct; I was strengthened in this view by the absolute identity of several hundred specimens attached to two vessels from Jamaica and Trinidad, in the West Indies, with one specimen from Charlestown, in the United States, sent me by Prof. Agassiz, and with several in three lots from the western tropical shores of South America: yet on close examination I can point out no one distinguishing character, either in the shell or animal’s body, excepting the longitudinal hyaline lines on parietes, due to the septa being externally visible. The presence of similar lines is variable in white vars. of B. amaryllis and amphitrite, and they are seen in very young specimens of B. eburneus: hence it is impossible to consider so trifling a character as specific; moreover, lately I have seen a British specimen with hyaline lines, and some few other specimens in an intermediate condition. Under the head of B. eburneus, I have stated that although that species and B. improvisus, which in the West Indies are associated together, are most readily discriminated when old, yet when young, they so closely resemble each other that the eye requires much practice to separate them. On account of this species and B. crenatus being sometimes associated together on the shores of England, I have pointed out under B. crenatus, the relative diagnostic characters of the two. The chief affinity of B. improvisus is certainly towards B. eburneus; but in the narrow, oblique, rounded, and smooth-edged radii, there is a relationship shown to the species in the last section of the genus, such as B. amaryllis, and more especially to the fossil B. dolosus: so close is the resemblance in the external appearance of the shell, and in the structure of the opercular valves, to the latter species, that I for some time did not discover their distinctness. Balanus improvisus has hitherto been overlooked by naturalists, and has probably been confounded with B. crenatus or balanoides.

Range and habits. — This species, as far as my experience goes, is commoner on the shores of Kent than on other parts of England: the first specimens which I met with, I owed to the kindness of Mr. Metcalf, they were attached to wooden stakes from Herne Bay, together with a single specimen of B. crenatus: I have seen other specimens from near Woolwich, from the Kentish oyster-beds, from Sandwich, and from Ramsgate. The only other British specimens which I have seen are from the River Itchen, in Hampshire, and from Loch Shieldaig, in Ross-shire (Mus. Jeffreys), from a depth of twenty fathoms. This species is often attached to wood. At Ramsgate, the specimens were attached to a small coasting vessel, and they must have been immersed five or six feet; they were associated with B. crenatus, and with a few of B. balanoides. In the Brit. Mus. there are specimens collected by Mr. Redman, from Nova Scotia, in North America. When her Majesty’s ship Beagle was beached at Santa Cruz, in Southern Patagonia, numerous specimens were found adhering to her copper bottom, some so small as to show that the species breeds in those latitudes. Near Monte Video, in the estuary of La Plata, I found many large, but much corroded specimens, adhering to some rocks in a small running stream of perfectly fresh water. The rise of the tide is here small, but at high water the specimens apparently were for a short time covered by the waters of the estuary, here itself only brackish, and occasionally almost fresh. I took home some specimens, and placing them in perfectly fresh water they continued for many hours expanding and retracting their cirri with perfect regularity and vigour. Here then we have a Balanus capable of living in fresh water, and likewise in the saltest seas: even brackish water is a deadly poison to several, probably to most, species of the genus; but this, as we have seen, is not the case with the allied B. eburneus. The water, I may add, at Woolwich, on the Thames, whence I have received B. improvisus, must at times be very brackish. I have already incidentally mentioned that the var. assimilis was attached in great numbers, associated with B. eburneus, tintinnabulum, and amphitrite, on vessels from the West Indies: one specimen sent me by Prof. Agassiz, from Charlestown, was attached to a specimen of B. eburneus; and, lastly, I have seen three sets of the same identical variety attached to shells from Guayaquil (in Mus. Brit. and Cuming), and from West Colombia. Here, then, we have the same species with an enormous range, from Nova Scotia and Great Britain to South Patagonia; and, which is the case with scarcely a single mollusc, it lives both on the eastern and western tropical shores of the South American continent.

 

23. BALANUS NUBILUS. Pl. 6, fig. 2 a-2 c.

Shell white, rugged: basis in parts imperfectly porose. Scutum with the articular ridge minute; adductor ridge prominent, forming a deep pit for the lateral depressor muscle: tergum with an internal patch of purple; apex produced, purple.

Hab. — California, Mus. Brit. and Aug. Gould; associated with B. glandula, and attached to wood.

I have seen two specimens of this species, brought by Lady K. Douglas from California; and two from Monterey, sent me by Dr. Aug. Gould. This is a very distinct species, coming nearer to B. porcatus than to any other species: it is also allied to B. cariosus. In the basis being in parts solid or not permeated by pores, it has claims to be placed in the next section, in which I at one time included it.

General Appearance. — Shell conical, rugged, sometimes furnished with sharp longitudinal ribs; dirty white. Orifice not large, oval, toothed. Radii rather narrow, with their summits oblique, much jagged. Basal diameter of largest specimen 2.1; height only 1.3 of an inch.

Scuta, broad, with the lines of growth prominent; internally, articular ridge very little prominent, sometimes hardly developed, but thick, ending downwards in a small free point. Adductor ridge prominent, blunt, produced straight downwards, making a deep longitudinal cavity for the lateral depressor muscle; in some specimens this cavity is almost arched over, so as to tend to be tubular, with a short ridge in the middle (Pl. 6, fig. 2 a): in other specimens there is no trace of this tubular structure. Terga, with the apex beaked, beak triangular, dull purple; the longitudinal furrow is so shallow as hardly to exist. The basal margin slopes down on both sides, with a nearly equable curvature towards the spur; hence the spur is broad in its upper part, and narrow at its obliquely truncated lower end. Internally, there is an elongated dark purple patch: the shallow articular furrow is of quite remarkable breadth; the articular ridge is medial, and the inflected scutal margin is not wide. The internal surface of the spur is formed into a ridge, which runs a little way up the valve, and is sometimes partially separated from the spur itself (fig. 2 c), making the basal extremity toothed or double. The crests for the depressores are pretty well developed.

Walls, moderately strong: inner lamina slightly ribbed: the denticuli on the bases of the parietal longitudinal septa are sharp: I could not see any transverse septa in the parietal tubes. The radii are rather narrow; their summits are remarkably jagged and very oblique; the septa are plainly denticulated on both sides, but chiefly on the lower side; each septum itself, towards the inner lamina of the radius, branches and divides: the interspaces are filled up nearly solidly. The alæ have apparently their summits less oblique than those of the radii: their sutural edges are finely crenated. The lower edge of the sheath is hollow underneath. The basis is flat; it is rather thin, and imperfectly porose; in parts it is not at all porose, in others it is traversed only by very minute pores: there is nevertheless, in some parts, even where the upper layer is not porose, an underlying, cancellated layer.

Animal’s body unknown.

 

24. BALANUS CORRUGATUS. Pl. 6, fig. 3 a, 3 b.

Shell white, longitudinally folded; radii narrow. Scutum internally without an adductor ridge.

Fossil, Sub-Appennine formations; Colle in Tuscany; Mus. Greenough.

I have seen only two specimens of this species attached to rock, collected by Mr. Greenough, at Colle, and kindly given by him to me. The species comes near to the living B. crenatus, also found fossil in deposits of this same age; it differs, however, distinctly from that species, in having its basis permeated by pores, and, in a less degree, in the sutural edges of the radii being more plainly crenated: the opercular valves of the two species closely resemble each other. This may be the B. stellaris of Bronn, but it is futile attempting to identify the species of this genus merely by external characters, even when aided, as in this case, by an excellent drawing of the shell.

General Appearance. — Shell conical, with broad rounded longitudinal folds; orifice of moderate size, oval; radii narrow, with their upper margins oblique; but the summits of both specimens had been much broken. Colour, as it appears, originally white. Basal diameter of largest specimen 3/4 of an inch.

Scuta, with the upper portion much reflexed; the articular ridge is very prominent, and the articular furrow of great width; when the valve is viewed from the outside the articular ridge is very conspicuous: there is no adductor ridge. Terga, with the longitudinal furrow very slight; the spur is from one third to one fourth of the width of the valve, and its basal end is blunt and almost truncated; it stands about half its own width from the basi-scutal angle. Internally, the articular ridge is very prominent, and the articular furrow narrow and deep, extending down the valve in the line of the spur.

Parietes: the parietal tubes are remarkably large, and I think this can hardly be an individual peculiarity: the tubes are crossed by many transverse septa, close down to the basis. The radii are narrow, and have jagged, oblique summits: their sutural edges have very distinct septa, barely denticulated, with the interspaces filled up solidly. The alæ have oblique summits; I was unable to make out the structure of their sutural edges. The Basis is very distinctly permeated by pores, which are crossed by transverse septa.

The shell and opercular valves of B. corrugatus so closely resemble the same parts in B. crenatus, that I should not be much surprised at seeing the two species graduating into each other, if a larger series of specimens, from beds intermediate in age between the Sub-Appennine formations and the present time, were obtained. If indeed the basis of B. crenatus were permeated by pores, the two species could hardly be discriminated.

 

 

Section D.

Parietes permeated by pores. Basis and Radii not permeated by pores.

 

25. BALANUS PORCATUS. Pl. 6, fig. 4 a-4 e.

BALANUS PORCATUS. Emanuel da Costa. Hist. Nat. Test. Brit.,  (1778).

LEPAS BALANUS. Linn. Syst. Naturæ (1767).

  ——  —   —— Born. Testacea Mus. Cæs. Desc., Tab. 1, fig. 4, (1780).

  ——  —   —— Chemnitz. Syst. Conch., 8 Band., Tab. 97, fig. 820, (1785).

BALANUS ARCTICA PATELLIFORMIS. Ellis. Philosoph. Transact., vol. 50, Tab. 34, fig. 18 (1758).

  ——  — SULCATUS. Bruguière. Encyclop. Method., Tab. 164, fig. 1 (1789).

LEPAS COSTATA and BALANUS. Donovan. British Shells, 1802-1804, Tab. 30, fig. 1, 2.

LEPAS SCOTICA. W. Wood. General Conchology, Pl. 6, fig. 3, sed non Lepas balanus, Pl. 7, fig. 3, (1815).

BALANUS ANGULOSUS. Lamarck (1818), in Chenu, Illust. Conch., Tab. 11, fig. 11.

  ——  — TESSELATUS. Sowerby (!). Mineral Conchology, Tab. 84 (1818).

  ——  — SCOTICUS. Brown. Illust. Conch. Great Britain, Pl. 7, fig. 2, sed non, Pl. 6, fig. 9 et 10 (1827); 2d edit., Pl. 53, fig. 1-3, 22, 23 et Pl. 54, fig. 1-3.

  ——  — GENICULATUS. Conrad. Journal Acad. Philadelphia, vol. 6, part 2,  (1830), Tab. 11, fig. 16.

  ——  ——  —   ——  — Aug. Gould (!). Report on the Invertebrata of Massachussetts, fig. 9 (1841).

Shell white, generally sharply ribbed longitudinally: radii with their summits almost parallel to the basis. Scutum longitudinally striated: tergum with the apex produced and purple.

 

Var. (a): Walls without longitudinal ribs. Mus. Brit., Cuming, Stutchbury, Jeffreys.

Hab. — South shores of England, Ireland, Scotland, Shetland Islands, Iceland, Davis’s Straits, 66° 30′ N.; Lancaster Sound, 74° 48′ N. (Mr. Sutherland). Maine and Massachussetts, United States. China (?). In deep water, common on shells, crustacea, and rocks, sometimes imbedded in sponges.

Fossil in the glacial deposits of Scotland, Uddevalla, and Canada; in the mammaliferous and Red Crag of England; Mus. Lyell, Sowerby, S. Wood, &c.

General Appearance. — Shell conical, somewhat convex; white, sometimes tinted yellowish, from the thin investing membrane; the produced tips of the terga are purple: the parietes of each compartment have from two to four strong, prominent, sharp, straight longitudinal ribs; these are sometimes irregular, and rarely, as will presently be described, they are absent. The radii are smooth and of considerable breadth; their summits are nearly parallel to the basis or only slightly oblique: hence the orifice is entire; it is rather small and ovate, being broad at the rostral end, and very sharp and narrow at the carinal end.

Dimensions. — The largest specimens which I have seen from Great Britain or Ireland, have been 1.3 of an inch in basal diameter: in Mr. Cuming’s collection, however, there was one much depressed specimen from the Shetland Islands, 2.1 in basal diameter: a regularly conical specimen from the coast of Massachussetts attained a nearly equal diameter; out of the glacial deposits in the Isle of Bute, Scotland, several specimens had this same diameter, namely, two inches, and were even more steeply conical, being 1.85 in height; some glacial specimens from Uddevalla and Canada, in Sir C. Lyell’s collection, were 1.7 in basal diameter. Hence, it appears, as we shall presently see is likewise the case with B. crenatus and Hameri, that northern specimens, and those from the United States and from the glacial deposits, often exceed in dimensions those from Great Britain or Ireland.

Scutum: the lines or ridges of growth are broad and prominent; they are divided into square beads by fine striæ, radiating from the apex: and hence the valve is longitudinally striated. Internally, the articular ridge is extremely little prominent; the adductor ridge, or what must be called such, runs straight down under the articular ridge, making a deep longitudinal pit for the lateral depressor muscle. Tergum: the apex is a little produced, and coloured purple, as well as the upper internal surface of the valve; there is no longitudinal furrow, only a very slight depression: the spur is placed close to the basi-scutal angle; it is rather long, and measured across the upper part, is half as wide as the valve: its lower end is truncated and rounded; the basal margin slopes towards it. Internally, a very small portion of the scutal margin is inflected: the articular furrow is shallow and broad: the crests for the depressores are feeble. In young specimens the spur is bluntly pointed.

The Parietes (4 e) have large square parietal tubes: in the upper part these are filled up solidly without transverse septa: the longitudinal septa are finely denticulated at their bases, and the denticuli extend unusually close to the outer lamina. In very young specimens the inner lamina of the parietes is ribbed, in lines corresponding with the longitudinal septa, as is the case with most species of the genus; but in medium and large-sized specimens, there are between the ribs, thus produced, from one to four smaller ribs, which do not correspond with any longitudinal septa; they are finely denticulated at their bases, and may be considered as the representatives of longitudinal septa which have not been developed and reached the outer lamina. I have seen no other instance of this structure, namely, the presence of a greater number of ribs, on the inner lamina of the walls, than there are longitudinal septa. The radii have their summits generally parallel to the surface of attachment, as is usual in the first section of the genus, but sometimes they are slightly oblique: the septa sometimes rudely branch a little, but they exhibit scarcely a trace of denticuli: the interspaces are filled up quite solidly. The alæ have their summits very oblique; their sutural edges are finely crenated.

Basis, rather thin, translucent, not permeated by pores; obscurely furrowed in lines radiating from the centre: the circumference is marked in a peculiar manner by the longitudinal septa, and by the tips of those intermediate, denticulated ribs, which occur on the inner lamina of the parietes.

Mouth: labrum with six teeth: mandibles with the fourth and fifth teeth small and rudimentary: maxillæ, with a small notch under the upper pair of spines; in the lower part there is a single large spine. Cirri, dark brownish purple, making a singular contrast with the white operculum and shell; first pair, with one ramus, having twenty-six segments, and about twice as long as the shorter ramus, having twelve or thirteen segments, with their front surfaces protuberant. In the second pair the segments are but little protuberant: third pair about one third longer than the second pair: sixth pair, elongated, having in the same individual forty-six segments; these segments have shield-shaped fronts, bearing five pairs of spines, with some minute intermediate bristles. There is the usual point at the dorsal base of the penis.

Range: Geological History. — This species is common on the shores of Scotland and Ireland; the most southern point of Europe whence I have happened to see a specimen is Tenby, in South Wales: but I have no doubt it is found further south; and Mr. Jeffreys, who knows this species well, has found it common on the extreme southern shores of England. In the United States, it is found on the shores of Maine and Massachussetts: northward, I have seen specimens from Iceland, from Davis’s Straits, and from Lancaster Sound, in lat. 74° 48′ north; these latter I owe to Sir J. Richardson. It is an inhabitant of deep water; in Mr. Thompson’s collection there are several specimens from the Bay of Belfast, marked twenty-five fathoms, and one group said to have come from “about fifty fathoms, on the coast of Antrim:” one specimen from Cape St. Anne, Massachussetts, is marked as having come from only five fathoms. This species is commonly associated, on both sides of the Atlantic, with B. crenatus, and sometimes with B. Hameri and Verruca Strömia: mollusca, such as pectens, modioli, and oysters, offer the most usual surfaces of attachment: I have, however, seen many specimens on crustaceans, on rocks, and even on the roots of the larger sea-weeds. This species is very common in the glacial deposits of Uddevalla, of Skien in Norway, and of Canada, and is associated with the same species as in the living state: I have seen, also, specimens from the same formation in the Island of Bute, Scotland. I have seen numerous specimens from the mammaliferous crag, and a few from the Red Crag of England. I owe to the kindness of Mr. J. de C. Sowerby an inspection of the original specimens of the B. tesselatus of the Mineral Conchology, which is certainly the present species.

Affinities. — This species is very distinct from every other; it comes nearest, as shown in all the characters derived from its opercular valves, to B. nubilus, and in this latter species we have seen the basis plainly tending to lose its pores and thus become solid. B. porcatus is perhaps allied in some degree to B. trigonus, and slightly to B. crenatus. The rather broad radii, with their summits hardly oblique, give this species a very different aspect from those species of the genus amongst which it must be placed.

Varieties. — A conical specimen, sent to me from the coast of Massachussetts, is remarkable from the radii not having been at all developed, being represented by mere fissures. I have seen a few specimens of var. (a), (one collected by Sir E. Parry in the arctic seas) which had a remarkably different aspect from the common forms, but which, after a careful examination of the opercular valves and of the animal’s body, I feel convinced are not specifically distinct: they are characterised by the walls being smooth and absolutely destitute of the external longitudinal ribs; by the shell being more cylindrical, with broader radii, and with the orifice larger and more rhomboidal; the walls and radii are much thinner, and the internal lamina is less plainly ribbed: the beak of the tergum is not purple. As most of these specimens had grown in a group crowded together, the difference of shape, and perhaps the thinness of the walls, is thus explained. In a specimen from Davis’s Straits, in Mr. A. Hancock’s collection, most of the above characters are in an intermediate condition; there are only a few external longitudinal ribs on the parietes; and the terga have not purple apices. In Mr. Cuming’s collection there are some fine, brilliantly white specimens (without opercula) from the coast of China; these have thin walls and radii, and the walls are not longitudinally ribbed, but they are not smooth: the orifice is not large, nor the shape of the whole shell cylindrical. It is just possible that these latter specimens may be a distinct and representative species, but I do not think so.

 

26. BALANUS PATELLARIS. Pl. 6, fig. 5 a-5 c.

LEPAS PATELLARIS, (Gmelin). Spengler. Schriften der Berlin. Gesellschaft, &c. b. i (1780), Tab. 5; Chemnitz, Neues Syst. Couch., Tab. 98, fig. 839.

Shell depressed; brown, generally with obscure longitudinal violet stripes: radii (in full-grown specimens) with their summits rounded and surfaces finely ribbed parallel to the basis: basis sometimes permeated by imperfect pores. Scutum internally with an adductor ridge.

Hab. — Bengal, on wood, Mus. Brit.; on a shell, Mus. Stutchbury; Philippine Archipelago (young specimen), Mus. Cuming. According to Spengler, on the Coromandel and Malabar coasts.

General Appearance. — Shell depressed, sometimes much depressed: orifice elongated, rhomboidal, but little toothed; surface smooth, but in old specimens sometimes with the walls slightly folded longitudinally. The radii are rather narrow, with their summits oblique; in old specimens their summits are rounded, and their whole surface finely ribbed parallel to the basis. Colour, in old specimens dirty brown, tinged with violet, sometimes in longitudinal bands, and with whiter irregular marks in the upper parts owing to disintegration: in young specimens the walls are regularly banded longitudinally, with violet-brown and dirty white; the radii being generally of a paler dirty red or violet. Basal diameter of largest specimen .9 of an inch.

Scuta, externally rather smooth; internally, articular ridge prominent, reflexed, with the lower edge hollowed out so as to be slightly hook-formed: adductor ridge small; there is a slight pit for the lateral depressor. Tergum, with the spur bluntly pointed, placed at about its own width from the basi-scutal angle; there is no longitudinal furrow, only a slight depression; carinal margin arched and protuberant: internally, articular ridge extremely prominent, running down in the direction of the middle of the spur: crests for the tergal depressores well developed.

Parietes, with the pores rather large; the internal lamina is very strongly ribbed, the ribs being but slightly denticulated at their bases: the parietal pores do not appear to be crossed by transverse septa: sheath closely attached to the walls. The radii have jagged oblique summits forming an angle of about 45° with the horizon; in old specimens they become more oblique and narrow: and are then very remarkable from their summits being arched and rounded, with a crenated edge, and with their whole surface transversely ribbed in horizontal lines; this is likewise the case with the recipient furrow in the opposed compartments: in young specimens the radii are externally quite smooth: the septa on the sutural edges are bluntly denticulated; the interspaces being filled up solidly. The alæ have their summits oblique, but much less oblique than the summits of the radii; their sutural edges are very finely crenated.

Basis thin, either quite solid, that is, not permeated by pores, but only furrowed in lines radiating from the centre, or permeated by pores towards the circumference, the pores being of very small diameter; — so that we here have an important character variable within the limits of the same species. Base flat, and this holds good, as remarked by Spengler, even when the specimens are attached to cylindrical pieces of wood.

 

Animal’s body unknown.

Affinities. — In the basis being sometimes permeated towards the circumference by pores, and by the colouring (the other species in this and the next section being dirty white), B. patellaris has almost as strong a claim to be ranked in the last as in the present section: in the rounded summits of the radii, and in the state of the basis, it, perhaps, shows more affinity to B. improvisus than to any other species; it is, however, almost equally allied to B. glandula.

 

27. BALANUS CRENATUS. Pl. 6, fig. 6 a-6 g.

B. CRENATUS. Bruguière. Encyclop. Method. (des Vers) 1789.

LEPAS FOLIACEA, var. a. Spengler. Skrifter af Naturhist. Selskabet, b. i, 1790.

  —— BOREALIS. Donovan. British Shells, Pl. 160 (1802-1804).

B. RUGOSUS. Pulteney (?) Catalogue of Shells of Dorsetshire, 1799.

  ——  —— Montagu (?) Test. Brit. 1803.

  ——  —— Gould (!). Report on Invertebrata of Massachussetts (1841), fig. 10.

B. GLACIALIS (?) J. E. Gray. Suppl. Parry’s Voyage, 1819.

B. ELONGATUS (!), CLAVATUS (!), Auctorum variorum.

Shell white: radii with their oblique summits rough and straight. Scutum without an adductor ridge: tergum with the spur rounded.

Hab. — Great Britain, Scandinavia, Arctic Regions as far as Lancaster Sound, in 74° 48′ N. (Mr Sutherland); Behring’s Straits (Captain Kellett); United States; Mediterranean; West Indies, (Mus. Brit.); Cape of Good Hope, (Mus. Krauss). Generally attached to shells and crustacea in deep water; sometimes to ships’ bottoms. Very common.

Fossil in glacial deposits of Scandinavia and Canada, Mus. Lyell; in the mammaliferous, and Red, and Coralline Crags, Mus. S. Wood, J. de C. Sowerby, Bowerbank; Miocene formation, Germany, Mus. Krantz.

I find, in most collections, this species confounded with B. balanoides; I have even seen the two species, placed by Leach, on the same tablet in the British Museum: B. balanoides is, moreover, generally confounded with Chthamalus stellatus; nor has any one hitherto separated the present species from B. improvisus. On the other hand, trifling varieties, both of B. balanoides and B. crenatus, have commonly been considered as specifically distinct. From these facts it will be seen in what confusion our commonest British species of Balanus have been left. After due deliberation, I have little doubt that this is the B. crenatus of Bruguière, and probably the B. rugosus of Montagu, but this latter author omits all reference to the really important diagnostic characters between this species and B. balanoides. The B. crenatus is certainly the B. rugosus of Dr. Aug. Gould. In various collections, I find specimens of B. crenatus, when coming from the arctic regions, called B. glacialis, arcticus, and borealis; though I have not met with an authentic specimen of the B. glacialis of Gray (‘Supp. Parry’s Voyage,’ 1819, p. ccxlvi), I have little doubt that it would prove to be the present species.

General Appearance. — White, usually of a dirty tint, from the yellowish or brownish persistent epidermis: conical, generally (fig. 6 a) with the parietes rugged and irregularly folded longitudinally; but sometimes much depressed and extremely smooth (6 b); often cylindrical and very rugged; occasionally club-shaped (6 c), the upper part being much wider than the lower: specimens in this latter condition sometimes have extremely narrow parietes, like mere ribs, and wide radii. The orifice in the cylindrical varieties is often most deeply toothed. The radii are generally narrow, and have jagged oblique summits; but not infrequently they are so narrow as to form mere linear borders to the compartments. The orifice is rhomboidal, passing into oval, either very deeply or very slightly toothed.

Dimensions. — The largest British specimen which I have seen was only .55 of an inch in basal diameter: specimens from Greenland and the northern United States frequently attain a diameter of three-quarters of an inch, and I have seen one single somewhat distorted specimen actually 1.6 of an inch in basal diameter. The specimens from the glacial deposits of Uddevalla and Canada appear, on an average, to attain as large or larger dimensions than those from the United States: on the other hand, the specimens from the mammaliferous and Red Crag are smaller, the largest being only .35 in basal diameter. When individuals have grown crowded together, their length is often twice, and even occasionally thrice, as great as their greatest diameter; thus I have seen a Greenland specimen 1.6 of an inch in length, and only .75 in diameter. In the British Museum there are some arctic specimens, one and a half inch in length, only half an inch in diameter at the summit (fig. 6 c), thence tapering downwards to a blunt point.

Scuta; the lines of growth are but little prominent: the surface is generally covered by disintegrating membrane. The upper ends are usually a little reflexed, so that the tips project freely as small flattened points. Internally, the articular ridge is highly prominent and somewhat reflexed: there is no adductor ridge, but a very distinct impression for the adductor muscle: the depression for the lateral depressor muscle is small, but variable. The terga are rather small: the spur is short, and placed at rather less than its own width from the basi-scutal angle; the basal margin slopes a little towards the spur, of which the lower end is rounded or bluntly pointed in a variable degree. There is no longitudinal furrow, hardly even a depression. Internally, the articular ridge is very prominent in the upper part; the crests for the tergal depressores are well developed, but variable.

Compartments. — The internal carinal margin of each compartment, from the sheath to the basis, generally, but not invariably, projects a little inwards beyond the general internal surface of the shell, in a manner not common with the other species of the genus: the basal edge of this projecting margin rests on the calcareous basis, and is crenated like the basal edges of the longitudinal parietal septa. The whole internal surface of the shell is ribbed, but the ribs are not very prominent. The parietal tubes are large, and are crossed in the upper part, and often low down, by transverse thin septa: the longitudinal parietal septa are only slightly denticulated at their bases; occasionally they divide at the basis close to the outer lamina of the parietes, making some short outer subordinate pores. In the circular furrow beneath the lower edge of the sheath, there are sometimes little ridges, dividing it into small cells: sometimes, however, this furrow is filled up by irregular knobs of calcareous matter. The radii are always rather narrow, and often they form mere linear ribbons of nearly uniform width along the edges of the compartments. Their summits or edges are always more or less irregular and jagged: they form an angle with the horizon of generally above 40°. Their septa are fine, and barely or not at all denticulated. The alæ have oblique summits: their sutural edges are rather thick and distinctly crenated. Basis flat, calcareous, very thin, with the surface slightly marked by radiating furrows, which furrows answer to the radiating pores that occur in the bases of most species. In a club-shaped arctic specimen, one inch and a half in length, the summit being half an inch and the base only one fifth of an inch in diameter, the basis was still calcareous, thick, and not permeated by pores.

Mouth: labrum with six teeth: mandibles with the fourth tooth minute or rudimentary, and the fifth generally confluent with the inferior angle. Maxillæ with generally, but not invariably, a small notch under the upper pair of great spines. Cirri, first pair with the rami very unequal in length, one ramus being nearly twice the length of the other; in a large specimen having a cylindrical shell the proportional numbers of the segments in the two rami of the first cirrus were ten to twenty-three; in a small conical specimen the numbers were only eight to thirteen. The second cirrus has only two or three more segments than the shorter ramus of the first pair: the third cirrus has one or two more segments than the second; but it is nevertheless decidedly longer than the second. On the dorsal surfaces of both segments of the pedicel of the third cirrus, there is a tuft of fine spines. The segments of these three pairs of cirri are not much protuberant in front. The segments of the posterior cirri have, each, four, or five, or six pairs of spines. Penis, with a straight, sharp, short point on the dorsal basis.

 

Range, habits, &c. — I have received specimens from all parts of the coast of Great Britain and Ireland, generally attached to crustacea and mollusca, and never hitherto from rocks uncovered by the tide. This species is also attached to floating timber, sticks, fuci, and occasionally to pebbles at the bottom of the sea. Mr. Thompson has sent me specimens from twenty-five fathoms depth in Belfast Bay: others on a Pinna from about fifty fathoms on the coast of Antrim; others from between three and six fathoms attached to Laminaria digitata: there is a specimen in Mr. Jeffreys’ collection marked forty-five fathoms. It is often associated, both on the coasts of America and Britain, with B. porcatus, and though these species are so distinct, yet when both have their surfaces similarly affected by being attached, as is often the case, to large Pectens, it is not at first easy, by external characters, to distinguish them, except by close inspection of the terga, which in B. porcatus are beaked and purple. The B. crenatus is sometimes associated in deep water with B. Hameri. At Ramsgate, in Kent, I saw a rudder of a ship, in which the two or three upper feet were thickly coated with B. balanoides, and the two or three lower feet with B. crenatus and improvisus mingled, together with a few of B. balanoides: occasionally vessels are thickly encrusted with this species, but I have never seen an instance of its concurrence with B. tintinnabulum and amphitrite — the commonest species on ships coming from the south. I have seen specimens from Greenland, Baffin’s Bay, the coast of Labrador, and other specimens marked simply, “Arctic regions,” and, again, others from the shores of Maine and Massachussetts. The arctic specimens, and those from the northern United States, are larger than the British. I have seen one single minute specimen on a crab, marked as having come from the Mediterranean. In the British Museum, amongst some specimens of B. eburneus, ticketed as having been sent from Jamaica, there was a small group of specimens, differing in no one essential respect from the common varieties of B. crenatus: at first I concluded that this was an erroneous habitat, and that the specimens had really come from the United States, where B. eburneus, is found as well as in the West Indies: for it appeared to me exceedingly improbable that an animal which can exist in lat. 75° N. should inhabit the hot shores of Jamaica: but subsequently I have received a specimen from Prof. Krauss, collected by himself in Algoa Bay, which is perfectly characterised, and even has the little cells in the furrow under the sheath: so that I am compelled to admit this enormous range and capability of resisting the most extreme climates. That this species should live in the tropical seas is the more surprising, as the large size of the specimens in the northern seas and in the glacial deposits, might fairly have been supposed to have indicated special adaptation for a cold climate. The great geographical range of this species accords with its range in time from the present day to the Coralline Crag period.

The specimens from the glacial deposits which I have examined, chiefly in Sir C. Lyell’s collection, are very fine and large; they are often associated, like the now living individuals, with B. porcatus and Hameri: they come from the well-known formation of Uddevalla and from Canada. There are well-characterised specimens in the mammaliferous Crag, at Bramerton and near Norwich, in Sir C. Lyell’s collection, and from Sutton and other places in the Red Crag of the eastern shores of England: these specimens are decidedly not only smaller than the glacial, but than the recent English specimens; for the largest Crag specimens which I have seen had a basal diameter of only .35 of an inch. The specimens which I have seen from the Coralline Crag, and some others sent me by Krantz from the miocene formation of Flonheim bei Abzei, in Germany, had not their opercular valves, yet I cannot doubt, considering how few species there are in the present section of the genus, that I have rightly identified them.

Diagnosis. — Under the head of B. balanoides I shall make a few remarks on the diagnosis between that and the present species; as B. improvisus is found on the British shores, sometimes mingled with B. crenatus, I may observe that, externally, the only difference consists in the edges of the radii in B. improvisus being much smoother and rounded, and in the whole shell being less rugged. Internally, in B. improvisus the porose basis, the presence of an adductor ridge on the under side of the scutum, the graduated teeth on each side of the central notch in the labrum, and the little inequality in length of the rami of the first pair of cirri, are clearly and amply diagnostic.

 

28. BALANUS GLANDULA. Pl. 7, fig. 1 a, 1 b.

Shell white; parietes with the internal lamina generally strongly ribbed longitudinally, with the pores imperfect and small, sometimes in part absent; radii narrow, with their summits rounded. Scutum with an adductor ridge; tergum with the spur truncated and rounded.

Habitat. — California, Mus. Cuming, Aug. Gould; attached to shells and wood, together with B. nubilus. Southern Pacific ocean, attached to Pollicipes polymerus; Mus. Brit.

General Appearance. — Shell steeply conical, or cylindrical and elongated; dirty white; walls rugged, longitudinally folded; radii narrow, with their summits very oblique and rounded; orifice toothed. Basal diameter of largest specimen half an inch.

Scutum, resembling externally that of B. crenatus; rather broad, surface smooth; articular ridge very prominent, and articular furrow very wide; hence, when the summits of the opercular valves are worn down, the two scuta together form a square projection indenting the two terga, as in B. balanoides. Internally, there is a small adductor ridge, on the lower side of which there is a pit, as if for a muscle. The depression for the lateral depressor muscle is small, but variable. Tergum without any longitudinal furrow, and hardly a depression: spur broad, with its lower end truncated and rounded; internally, articular ridge very prominent; crests for the depressores well developed.

Compartments: — The internal surface of the parietes is smooth in the upper part beneath the sheath, but generally very strongly ribbed in the lower part, the ribs being plainly denticulated at their bases; in other specimens, the ribs are very small, and even in parts quite obsolete. The parietal pores are short and imperfect, sometimes reduced to an extremely minute size, to be detected only when the walls are broken across near the basal edge, and most carefully examined; occasionally not even a trace of a pore exists. Hence in this respect, this species offers a singular case of variation. The radii are narrow, and of nearly the same width from top to bottom; their very oblique summits, when well preserved, are smooth and rounded; their sutural edges are ribbed or crenated with extremely fine, smooth septa; the recipient furrow is plainly marked by these septa. The sutural edges of the alæ are crenated; their summits are less oblique than those of the radii.

Basis, thin, finely furrowed in lines radiating from the centre; margin sometimes deeply sinuous.

Mouth: labrum with the central notch rather widely open, with four teeth on each side of it: palpi with very short spines along their inner margins: mandibles with the fourth and fifth teeth forming mere knobs: maxillæ small, with a mere trace of a notch under the two great upper spines. Cirri; first pair with the rami unequal by three or four segments, the longer ramus being only one quarter of its own length longer than the other ramus. Second pair short, with the segments (and those of the shorter ramus of first pair) somewhat protuberant. Third pair with the rami one third longer than those of the second pair. Sixth pair with the upper segments elongated, and bearing six or seven pairs of spines.

Affinities. — This species in general appearance closely approaches B. crenatus and balanoides, and it is related to them in many essential parts, such as in the opercular valves. It agrees with B. balanoides, and differs from B. crenatus, in the smallness and imperfection of the parietal pores, and in the radii having rounded summits; it agrees with B. crenatus in the structure of its basis, and in the prominent longitudinal ribs on the internal surface of the parietes, and differs from that species in the spur of the tergum being squarer, and in the scutum having an adductor ridge.

Range. — From the appearance of the Californian specimens, I suspect that they had adhered to tidal shells and to wood. The specimens in the British Museum, adhering to Pollicipes polymerus, consist of two lots, one of unknown origin, and the other certainly brought from the southern half of the Pacific Ocean by Sir James Ross: it deserves notice, that the Pollicipes polymerus, the supporting object, ranges from California to the southern Pacific Ocean.

 

 

Section E.

Basis membranous.

 

29. BALANUS BALANOIDES. Pl. 7, fig. 2 a-2 d.

LEPAS BALANOIDES. Linn. Fauna Succica, 1746, et Syst. Naturæ, 1767.

  ——  ——   —— O. Fabricius. Fauna Groen., , 1780.

  ——  ——   —— ET CLIVATUS. Montagu (!). Test. Brit., 1803.

BALANUS VULGARIS (?) Da Costa. Hist. Nat. Testacea, Pl. 17, fig. 7, 1778.

  ——  — OVULARIS ET ELONGATUS. Aug. Gould (!). Report, Invertebrata of Massachussetts, figs. 7 and 8, (1841).

  ——  — PUNCTATUS, CYLINDRICUS, ELONGATUS, FISTULOSUS CLAVATUS. Auctorum variorum. Sed non B. punctatus, Bruguière, Encyclop. Method., et non B. punctatus, Montagu, Test. Brit.

Parietes either solid, or cancellated, or rarely formed by a single row of pores. Tergum, with the spur bluntly or sharply pointed.

Var. (a) with the parietes permeated by tubes; spur of tergum sharply pointed; segments in the posterior pairs of cirri, bearing from eight to ten pairs of spines.