83 



Gen. 20. Pseudotryphosa, G-. 0. Sars, n. 



Syn: Trypliosa, Stebbing (ex parte). 



Body rather tliickish, with the anterior coxal plates comparatively small 

 and densely crowded together. Metasome powerfully developed, with large 

 epimeral plates. Eyes imperfectly developed. Antennae rather elongated but 

 powerful in structure, inferior ones somewhat longer than the superior, fla- 

 gella provided in both sexes with wery distinct alternating calceolae. Kpi- 

 stome not projecting in front of the broadly rounded anterior lip. Posterior 

 lip membranous, with narrowly produced diverging lateral corners. Mandibles 

 rather strong, molar expansion well developed, palp moderately slender and 

 originating at about the same level as the latter. Maxillae about as in Tn/- 

 pliosa. Maxillipeds with the masticatory lobe short and broad, scarcely reach- 

 ing the end of the antepenultimate joint of the palp; the latter rather robust, 

 with the terminal joint claw-like. Anterior gnathopoda much stronger than 







in the 2 preceding genera ; propodos rather large, imperfectly siibcheliform, 

 the palmar edge being not distinctly defined ; dactylus very elongated and 

 curved. Posterior gnathopoda slender, propodos gradually widening distally 

 and not produced at the tip beneath the minute dactylus. Pereiopoda power- 

 fully developed, basal joint of the 3 posterior pairs large and laminar, suc- 

 cessively increasing in size posteriorly. Last pair of uropoda considerably 

 projecting beyond the preceding pair, both rami lanceolate and setous on the 

 inner edge. Telson large, gradually tapering distally and deeply cleft. 



Remarks. --I have felt justified in establishing this new genus to include 

 the remarkable form previously characterized by me under the name of Icli- 

 nopus umbonatus. The closer anatomical examination of this form, instituted 

 subsequently, has indeed shown it to be very different from Idniopit* and not 

 to be properly referred to any of the previously established genera. Besides 

 this species, the form described by the Rev. Mr. Stebbing from the Challenger 

 Expedition as Trypliosa antetmipotens quite undoubtedly belongs to the same genus. 



34. Pseudotryphosa umbonata. G-. 0. Sars. 



(PI. 29, fig. 2.) 

 Ichtiopus umbonatus, G. O. Sars, Oversigt af Norges Crustaceer I, p. 79, PI. 3. fig. 2. 



Body somewhat tumid, with the back broadly rounded. Cephahm 



' about the length of the 1st segment of mesosome, lateral corners drawn out to 



an acute point. First pair of coxal plates very small, scarcely deeper ilian 



the corresponding segment, and tapering inferiorly ; the 3 succeeding pairs 



somewhat deeper than the body; 4th pair deeply emarginated pnst.-rinrly and pro- 



