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.