L. scutis terga amplè obtegentibus: carinâ intus concavâ: rostro squamarum subjacentium latitudinem vix æquante: lateribus, squamas subjacentes sesquitertio superantibus; superficie internâ latè ellipticâ: pedunculi squamis superioribus verticillum secundum pæne quadruplo superantibus.
Scuta largely overlapping the terga: carina internally concave: rostrum hardly as wide as one of the subjacent scales: latera with their internal surfaces broadly elliptical, as long as two and a half of the subjacent scales: upper scales of the peduncle nearly four times as large as those in the second whorl.
Mandibles with an equal number of pectinations between the first, second, and third main teeth: maxillæ notched, edge nearly straight: posterior rami of the second and third cirri, with their basal segments not paved with bristles: caudal appendages slightly exceeding in length the pedicels of the sixth cirrus.
New South Wales, Australia, imbedded in a Conia, (unique specimen,) Mus. Stutchbury.
Valves thin, white, translucent; upper layers of growth well preserved, excepting on the terga. A large portion of the carina projected freely. The teeth on the projecting margins of the growth-layers are broad, blunt, and often stand rather distant from each other.
Scuta (Pl. VIII, fig. 3 a), triangular, internally concave with no distinct pit for the adductor muscle. The scuta largely overlap the terga.
Terga (fig. 3 b) approaching to rhomboidal; basal angle rectangular, almost central, and consequently the exterior longitudinal ridge, which is rounded, is likewise nearly central.
Carina, internally concave, with no trace of a central internal ridge in the upper free portion; the growing or corium-covered surface is transversely oval, and is as wide as the widest part of the terga.
Rostrum, exceedingly minute, enlarged at each zone of growth, not so wide as the immediately subjacent scale on the peduncle.
Latera (fig. 3 c), in width equalling two and a half of the upper peduncular scales, or about one fourth or one fifth of the width of the carina; growing surface, (or a section parallel to the layers of growth,) broadly elliptic, pointed at both ends.
Peduncle, about twice as long as the capitulum; the scales of the uppermost whorl are quadrilateral (fig. 3 d), and nearly four times as large as those in the second whorl; these latter are about twice as large as those in the third whorl, which are very little larger than the small, almost equal-sized, equally distant, round beads scattered over the rest of the peduncle, down to the basal cup. All these scales are dentated, the upper rows most plainly and only on their basal margins; the lower little beads are very slightly crenated round their entire margins; they are mingled with star-headed spines (fig. 3 e) of yellow chitine. Basal calcareous discs thin, plainly marked exteriorly by concentric lines of growth, and covered by the usual yellow membrane, including the horny, spindle-shaped bodies.
Size and Colours. — The whole specimen, including the peduncle, was only one fifth of an inch in length; the capitulum being 3/40ths of an inch in width. I do not know whether the specimen had attained its full size, but think this is probable, as a large-sized species would not have made its habitation in one of the valves of so small a shell as a Conia. Shell white, exterior membrane, where preserved, yellow, and bearing small spines. Thoracic segments, the lower segments of the second, third, and fourth cirri, all the segments of the first cirrus and the trophi, slightly mottled with darkish purple.
Mouth. — The teeth or beads on the crest of the labrum are blunt, few, not very small, and equidistant.
Palpi, bluntly pointed.
Mandibles, with the three main teeth nearly equal in size; the pectinations are equal in number, namely, only three between the first and second, and the second and third main teeth; the inferior angle is coarsely pectinated, with one central spine much longer than the others; the distance between the tips of the first and second main teeth, equals that between the second tooth and the inferior angle.
Maxillæ, with the two upper spines very large; beneath them there are two small spines, and a considerable notch; the inferior part of the edge is nearly straight, bearing about thirteen pairs of spines, obscurely divided into two groups, the lower spines being smaller than the upper ones. The upper convex margin is hirsute with long hairs.
Outer Maxillæ, blunt, with the inner margin slightly concave; continuously, but thinly clothed with spines.
Cirri. — The segments of the three posterior pairs bear four pairs of spines, with the usual intermediate fine spines; dorsal spines thin and thick mingled together. First cirrus, short, with the anterior ramus rather the thickest and shortest; all the segments thickly paved with bristles, except the two terminal segments, of which the ultimate one bears some serrated spines of most unusual length, namely, equalling within one segment the entire length of the ramus. I presume that these spines serve as feelers. Second cirrus; anterior ramus much thicker and considerably shorter than the posterior ramus; six basal segments paved with bristles, the two terminal segments having the usual structure; posterior ramus with all its nine segments on the usual structure. Third cirrus, longer, to a remarkable degree, than the second cirrus, with its anterior ramus having the four basal segments paved, and the seven terminal ones on the usual structure; posterior ramus with twelve segments, of which none are paved. The pedicels of the second and third cirri thickly and irregularly clothed with spines. The upper segments of the pedicels of all the cirri are unusually long.
Caudal Appendages, longer than the pedicels of the sixth cirrus, by barely one third of their own length. Segments much elongated, seven in number; I may add for comparison that each ramus of the sixth cirrus contained, in this specimen, sixteen or seventeen segments.
General Remarks. — It is difficult to give obvious characters, (excepting the smallness of the rostrum compared with the scales on the peduncle,) by which this species can be externally discriminated from L. dorsalis, L. Nicobarica, and L. Rhodiopus; yet almost all the valves differ slightly in shape. In this species alone, (the peduncle of L. Rhodiopus is not known,) the lower, microscopically minute, bead-like scales of the peduncle are crenated, though obscurely, all round. In the animal’s body, the diagnostic characters are strongly marked; — the long spines on the terminal segment of the first cirrus, — none of the segments in the posterior rami of the second and third cirri being thickened and paved with bristles, — the pectinations being equal in number between the main teeth of the mandibles, — are all characters exclusively confined to this species.