Pollicipes elegans. Lesson. Voyage de la Coquille, tom. ii, , 1830, et Illust. Zool., Pl. xxxix, 1831.
—— —— — ruber. G. B. Sowerby. Zoolog. Proc., 1833, .
P. capitulo, valvarum duobus aut pluribus sub-rostro verticillis instructo: valvis et pedunculi squamis rufo-aurantiacis: squamarum verticillis densis symmetricè dispositis.
Capitulum with two or more whorls of valves under the rostrum: valves and scales of peduncle reddish-orange; the latter symmetrically arranged in close whorls.
Maxillæ with three tufts of fine bristles, separated by larger spines; segments is in the first cirrus more than half the number of those in the sixth cirrus; caudal appendages multi-articulate; filamentary appendages attached to the prosoma.
Coast of Peru, Payta, attached to wooden posts, according to Lesson: Lobos Island, Peru, Mus. Cuming: West Coast of Mexico, Tehuantepec, on an exposed rock, according to Hinds.
The resemblance of this species is so close to P. cornucopia, that it is quite useless to do more than point out the few points of difference. Valves of the capitulum and scales of the peduncle, coloured (after having been in spirits,) reddish-orange. In a specimen in which the capitulum was 1.3 of an inch in length, there were three whorls of valves below the carina; in this large specimen altogether there were about eighty valves; in medium-sized specimens, the number is about the same as in P. cornucopia. The upper latus, (viewed internally,) has an area about twice as large as that latus, which corresponds to the interspace between the carina and terga; whereas in P. cornucopia the upper latus is only slightly larger than this same valve. The apex of the basal internal margin of the carina is here rounded, instead of being square, as is generally the case with P. cornucopia. The strong membranous margin of the orifice of the sack, in its upper part, is almost one third as wide as the widest part of the terga, whereas in P. cornucopia it is only one fourth of this same width. The peduncle apparently is rather longer, compared with P. cornucopia, and the calcareous scales on it perhaps a little larger in proportion.
In a very young specimen, with the capitulum barely exceeding 1/20th of an inch in length, I could distinguish the sub-rostrum, sub-carina, the upper, and some of the lower latera.
Filamentary Appendages. — These, in a medium-sized specimen, are arranged on the prosoma in four longitudinal approximate rows, there being twelve in each row; those in the two outer rows are only half the length of those in the two inner rows; those nearest the thorax are the longest; there are some papillæ outside the outer rows. In a very large specimen with its capitulum 1.3 in length, these filaments were very much more numerous, and some were placed on the first segment of the thorax, and at the bases of several of the posterior cirri. Some of the filaments are bifid, trifid, and even branched. In all the specimens, at the bases of the first pair of cirri, there are, on each side, a pair of filaments, (one below the other,) pointing upwards, less than half as long as those on the prosoma: also on each side of the mouth, there is a longer and thicker filament, pointing upwards, with a few very minute scattered spines on it; the apices of these three pair of filaments, as well as of some of the others, are roughened with very minute pectinated scales. All these filaments were gorged with the branching testes.
Mouth. — The parts are closely similar to those in P. cornucopia; in the mandibles, the interspace between the third tooth and the inferior angle, is slightly pectinated: in the maxillæ, there are six or eight pairs of spines between the two upper tufts of fine spines.
Cirri. — These are in most respects similar, to those of P. cornucopia. In a specimen in which the sixth cirrus had eighteen segments, the shorter ramus of the first pair had ten segments, of which the five lower segments were thick and clothed with doubly serrated spines. In the second cirrus the anterior ramus had fifteen segments, of which the four basal ones were highly protuberant, and thickly clothed with spines. These spines, and some on the third cirrus, and a few on the first cirrus, have peculiar bent teeth, presently to be described under P. polymerus. These singularly toothed spines are absent in P. cornucopia. From the above numbers, we see that the first and second pairs of cirri have more segments in proportion to the sixth pair, than in P. cornucopia; and in the second pair, a fewer proportional number of the basal segments are protuberant and thickly clothed with spines.
Caudal Appendages, shorter than the lower segments of the pedicels of the sixth cirrus, with only four articulations; rather constricted near the base.
The Ovigerous Fræna consist of very long and prominent folds, thinning out to nothing towards the bases of the scuta, but not furnished, as far as I could see, with glands, and therefore not normally functional.
Diagnosis with P. cornucopia. — The reddish-orange colour of the valves alone suffices. There is a very slight difference, in the larger proportional size of the upper latera, and in the outline of the basal margin of the carina. In the maxillæ there is, in P. elegans, a greater width between the two upper tufts of fine spines. In the cirri, the segments in the first pair, are more than half as many as those in the sixth pair; in the anterior ramus of the second pair, only 4/15ths of the segments are protuberant and brush-like, whereas in P. cornucopia 5/12ths are in this condition.