Peduncle, narrower, but generally longer than the capitulum; upper part encased with small calcareous scales, with their apices curved inwards, and overlapping each other. The inner surface of each scale is triangular, with the basal margin protuberant. The scales continue to grow or be added to, only in about the ten upper whorls, which form but a small part of the whole peduncle; in the lower part, the scales become further and further separated from each other. The surface of attachment, in full-grown specimens, is broad; but in two very young specimens, which I removed with great care after the action of potash, I found the peduncle ending in a filiform prolongation, such as often occurs in [Scalpellum vulgare] and in [Lepas fascicularis]. At the extremity of the pointed peduncle, there were seated the larval prehensile antennæ, of which the following measurements are given to show how minute they are.
| Inch. | |
| Length, from apex of disc, to the further edge of the basal articulation | 20/6000 |
| Breadth of basal segment, in broadest part | 6/6000 |
| Hoof-like disc, length of | 6/6000 |
| Ultimate segment, entire length of | 6/6000 |
| Ultimate segment, breadth, in broadest part | 6/20000 |
The disc resembles a broad, rounded hoof, very little longer than broad, and narrowed in at the heel; the apex is not at all pointed, and bears some minute and thin spines. There is one large spine on the under side of the disc; and another on the basal segment, on the outside, in the usual position. The ultimate segment is long and thin; it has a notch on the inner side (the segment supposed to be stretched forward), bearing two or three long flexuous spines; and there are three or four other spines on the summit: altogether there is a close resemblance with the antennæ in Scalpellum, excepting that the hoof-like disc is not here pointed.
Colours.—Valves internally tinted, in parts, grey; peduncle, brown; corium of sack, purplish-brown, of peduncle, rich coppery brown; cirri, banded dorsally, and with the front surfaces of the segments, purplish-brown. Edge of the orifice of sack, fine crimson red. The specimen here described had been dried for a few weeks, and was then moistened.
Dimensions.—The largest specimen which I have seen, in Mr. Cuming’s collection, had a capitulum 1 and 4/10ths of an inch long; a fine specimen, from Teneriffe, was 9/10ths in length. In a specimen with a capitulum 1/20th of an inch long, and about the same in breadth, there were eighteen valves; so that, besides the principal valves, five pair of latera, the sub-carina, and sub-rostrum, were already developed, and on the upper part of the peduncle, there were many calcareous scales.
Filamentary Appendages.—The prosoma is well-developed, with thirteen or fourteen pair of short, blunt filaments, placed close together in two longitudinal rows; those nearest the thorax are the longest; outside this double row, on each side, there is a row of papillæ, indicating a tendency to the formation of two other rows of filaments. There is a pair of longer filaments, one on each side of the mouth, pointing upwards, and thinly clothed with long spines; at the bases of the first pair of cirri there is a second pair of filaments, shorter and bearing a few minute spines. The bottom of the sack is studded with small rounded papillæ, with roughened summits.
Mouth, not placed very far from the adductor muscle.
Labrum, highly bullate, equalling, in its longitudinal diameter, the rest of the mouth; upper part square, not overhanging the lower part; there are some small teeth on the crest.
Palpi, oval, outer and inner margins nearly alike, thickly clothed with spines.
Mandibles, with three very strong, yellow teeth; inferior point broad, coarsely pectinated. In one specimen, on one side, the third tooth was represented by two smaller teeth.