Anatifa spinosa. Quoy et Gaimard. Voyage de l’Astrolabe. Pl. xciii, fig. 17.
P. capitulo valvarum uno aut pluribus sub-rostro verticillis instructo: laterum pari superiore vix inferioribus longiore: membranâ valvas tegente (post desiccationem) subfuscâ flavescente: pedunculi squamis inæqualibus, non symmetricis: verticillis longiusculè distantibus.
Capitulum with one or more whorls of valves under the rostrum: upper pair of latera only slightly larger than the lower latera: membrane covering the valves (when dried) light yellowish-brown: scales of the peduncle of unequal sizes, unsymmetrical, arranged in rather distant whorls.
Maxillæ, with the edge square and straight: caudal appendages uniarticulate: filamentary appendages, none.
New Zealand. Mus. Jardin des Plantes, Paris: Mus. Cuming.
Capitulum, flattened, triangular, broad, with the valves varying in number, in full-grown specimens of the same size, from 30 to above 60; the scuta, terga, and carina are very much larger than the other valves; the rostrum, however, is nearly half the size of the carina; the remaining valves are exceedingly small. In some specimens there is only one whorl under the carina; in other specimens there are distinctly two whorls. The scuta, terga, and carina stand pretty close together; they are moderately thick, and are covered, in chief part, by yellowish-brown membrane, which is destitute of spines.
Scuta, triangular, broad, basal margin slightly protuberant.
Terga, as large as the scuta, flat, regularly oval, basal point blunt and rounded.
Carina very slightly curved, triangular, internally rather deeply concave, basal margin straight. The inner and growing surface is four fifths of the entire length of the valve. In half-grown specimens the apex projects a little outwards.
Rostrum, small, much curled inwards; the basal margin is much hollowed out; the inner surface is broadly triangular, more than twice as wide as high, and about one fourth of the entire length of the valve. The remaining valves, about 26 in number, do not correspond on the opposite sides of the same individual, they are exceedingly small, with the sub-carina, sub-rostrum, and three pairs of latera a trifle larger than the lower latera, which are generally arranged in two whorls. In shape all the latera are nearly alike; they consist of flattened styles, with their inner surfaces transversely oval, and more or less elongated, the larger ones being most elongated.
Peduncle, broad, barely as long as the capitulum. The calcareous scales are irregularly shaped, minute, elongated and pointed, placed in separate transverse rows, and crowded together in each row. Only the scales in the uppermost row grow regularly; but some of the lower scales continue to be added to irregularly, and hence are the largest. On the other hand, the lower part of the peduncle, from the first formed scales having been worn away, is often quite naked. From this cause, and from the continued and irregular growth of some of the lower scales, the rows in this part of the peduncle, generally become irregular. The surface of attachment is broad.
In a half-grown specimen, with a capitulum only 3/10ths of an inch long, all the lower valves were considerably larger in proportion to the scuta, terga, and carina, than in full-grown individuals.
Size and Colours. — Length of capitulum in the largest specimen, 7/10ths of an inch; breadth, slightly exceeding the length. Colours after having been long in spirits — upper part of sack, thorax, pedicels of cirri, and penis, clouded with fine purple; cirri banded with the same; exterior convex surface of the outer and inner maxillæ and palpi dark purple; prosoma yellow. The membrane of the peduncle and of the capitulum is dirty yellow, with bands of purple between some of the valves.
Filamentary Appendages, none. Ovigerous fræna placed near the middle of the basal margin of the scuta; small, semi-oval, with an elliptical ring of bead-like glands; glands seated on long footstalks.
Mouth. — Labrum far produced towards the adductor muscle; upper part highly bullate, nearly equalling the longitudinal diameter of the rest of the mouth, and very slightly overhanging the lower part; crest with very minute bead-like teeth.
Palpi, with their inner margins considerably excised, most thickly clothed with spines.
Mandibles, with three strong teeth, two unequal-sized small teeth being placed between the first and second, thus making five altogether; inferior angle broad, pectinated.
Maxillæ, with its edge broad, straight, bearing about twenty pairs of spines, shorter than the large upper spines.
Outer Maxillæ, with the bristles in front, continuous, and without any notch; exterior surface with a prominence clothed with long spines. Olfactory orifices slightly prominent.
Cirri. — First cirrus placed near to the second; posterior cirri not much elongated, with their segments slightly protuberant, bearing four pairs of spines, of which the lower pair is small; spines slightly serrated. In the lower segments, these spines are exceedingly unequal in length, the inner spines on both rami, not being above one fourth of the length of the outer corresponding spine in each pair. The tufts intermediate between these pairs, are not very large: on the lateral upper rims there are some strong, short spines: dorsal tufts with short, thick spines. First cirrus about three fourths as long as the second cirrus, with numerous tapering segments, three or four of the lower ones being thick and protuberant: in the first cirrus there are eleven segments, and in the sixth cirrus, seventeen. Second cirrus, with the anterior ramus slightly thicker than the posterior ramus: a few of the basal segments of both rami are protuberant, and thickly clothed with spines. In the third cirrus, the two rami are nearly equally thick, with some of the basal segments in both clothed, like a brush, with spines. In these brushes on the first, second, and third cirri, most of the spines are doubly toothed, each tooth being simply conical.
Caudal Appendages, small, much flattened, straight on the exterior side, and curved on the inner side, with a row of short, rather thick spines on the crest, and a few on the exterior margin.
The Affinities of this species will be given under the head of the following, P. sertus.