The Isopods of the Pacific Coast of North America. 321 seem to have been well ossified, but much constricted, and all those preserved belong to the abdominal region. Nothing can be added to the description of the dorsal scutes given by Davis ; but appearances suggest that at the broken hinder end of the fossil the row of scutes terminates, while the dorsal fin begins. The only scales shown are those of the two swallowed fishes in the abdomen. On the whole, it seems probable that Pantopholis will prove to be a member of the same extinct family of Scopeloids as Enchodus. It is remarkable for the length and slenderiiess of the abdominal region, the large size of the pectoral fins, and the unusually numerous median dorsal scutes. XXXIV. — Key to the Isopods of the Pacific Coast of North America, xoith Descriptions of Tvoenty-tijoo new Species. By Hareiet Richardson. [Concluded from p. 277.] IV. ASELLOTA. Analytical Key to the Families of Asellota*. a. Lateral parts of ceplialon scarcely expanded. Eyes, when present, small, lateral. Peduncle of inferior antennre without small accessory appendage outside of third joint. Legs ambula-tory, except first pair, which are distinctly sub-cheliform ; legs with dactylus generally uniuugiii-culate. First pair of pleopoda in female very small, not operculiform. Outer lamella of second pair very large and iucrusted, so as to form, together with corresponding lamellce of other side, a sort of operculum, covering the two suc-ceeding pairs XI. AsELLiDuE. %', Lateral parts of cephalou usually lamellar ly ex-panded. Eyes, when present, usually subdorsal. Peduncle of inferior antennae generally with small accessory appendage outside of third joint. Legs subequal in length with dactylus, generally bi-or triuno:uiculate ; first pair sometimes prehensile. First pair of pleopoda in female transformed into a single large opercular plate. Outer lamellae of two succeeding pairs narrow and confluent with basal part XII. Janirid^. • Sars, Crust, of Norway, ii. 1897, pts. 6, 6, pp. 95, 98.
BioStor
