83 



Gen. 20. Pseudotryphosa, G. 0. Sars, 11. 



Syn : Tryphosa, Stebbiug (ex parte). 



Body rather tliickisili, with the anterior coxal plates comparatively small 

 and densely crowded together. Metasome powei'fnlly developed, with large 

 epimeral plate.s. E3-es imperfectly developed. Antennae rather elongated but 

 powerful in stri^cture, inferior ones somewhat longer than the superior, fla- 

 gella ]n-ovided in botli sexes with wery distinct alternating calceolse. li\n- 

 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 Try- 

 phosa. 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 subcheliform, 

 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 po.sterior pairs large and laminar, suc- 

 cessively increasing in size posteriorly. Last pair of uropoda considerably 

 projecting be_)-ond the preceding pair, both rami lanceolate and setous on the 

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



RemarJis. — I have felt jiistified in establishing this new genus to include 

 the remarkable form ])reviousl3r characterized by me under the name of Ich- 

 nopiin umbonafns. Tlie closer anatomical examination of this form, instituted 

 subse([uently, lias indeed .shown it to be very different from Iclm.opnf: 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 Tryplofia antennipotcns ([uite undoubtedly belongs to the same genus. 



34. Pseudotryphosa umbonata. (i. 0. Sars. 



(PI. 29, fig. 2.) 

 Ichnopus umhonatus, G. O. Sar.s, Oversigt af Norges Crustaceor I, p. 79, PI. 3. fig. 2. 



. Body somewhat tumid, wath the back broadly rounded. Cephalon 

 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 than 

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

 somewhat deeper than the body ;. 4th pair deeply emarginated posteriorl3' and pro- 



