82 U.S. NATIONAL MUSEUM BULLETIN 2 60 



setulose molar. The two setulose subgenera would be distinguished by 

 the presence ( ?name) or absence (subgenus TrijplioseUa) of an acces- 

 sory dactylar tooth on gnathopod 1 ; however, a monographer of the 

 genus may find that the presence or absence of the dactylar tooth is 

 polyphyletic and thus would warrant erection of subgeneric names 

 only as marks of convenience and not relationship. The same may be 

 foimd to be true of the loss of molar setules when and if more species 

 like L. h'doba are discovered. 



The subgenus without name mentioned above might be Tmetonyx if 

 that genus were synonymized with TryphoseUa but the distinctly quad- 

 rate, nontapering coxa 1 seems to be of significant generic value. 



TryphoseUa metacaecula, new species 



FiGUKE 38 



Diagnosis. — Eyes absent; lateral cephalic lobes broad but acute; 

 antenna 1 with slight dorsodistal protrusion on article 1, accessory 

 flagellum biarticulate, antenna 2 very slender, article 5 about two 

 thirds as long as article 4 ; epistome nearly flat anteriorly, not exceed- 

 ing slight anterior lobe of upper lip (reconstructed in figure) ; article 

 3 of mandibular palp scarcely more than one third as long as article 

 2; spines of outer plate of maxilla 1 slightly thickened and inter- 

 mediate in stoutness between those of typical ^'"TryplioscC and Hij)- 

 fomedon; lobes of maxilla 2 subequal in length ; spines of outer plate 

 of maxilliped small and distinctly articulated ; coxa 1 posterodistally 

 beveled and tapering strongly; gnathopod 1 slender, article 5 longer 

 than 6, palm oblique but short, dactyl with large accessory tooth ; ar- 

 ticle 5 of gnathopod 2 short, about CO percent as long as article 2, of 

 medium stoutness, article 6 subrectangular, anterior margin scarcely 

 convex, palm chelate, dactyl large, fitting palm and entire distal end 

 of article 6; pereopods poorly setose, distal ends of sixth articles of 

 pereopods 1 and 2 with slightly enlarged spine weakly curved apically 

 (one on each side of dactyl) , spines smaller and straight on pereopods 

 3-5; pereopods 3-5 subequal in length to each other, short for the 

 genus; pleonal epimeron 1 posteroventrally romided, 2 sharply quad- 

 rate, 3 prolonged into short, acute tooth; pleonite 4 with small, sub- 

 triangular, blunt dorsal hump ; uropods all extending equally, uropod 

 3 of normal tryphosa dimensions, inner ramus exceeding apex of 

 article 1 of outer ramus, article 2 of outer ramus 60 percent as long as 

 article 1; telson cleft nearly three fourths of its length, each apex 

 slightly notched, each bearing one spine. 



HoLOTYPE. — AHF No. G132, ?male, 3.0 mm. Unique. 



Tyte-locality.— Station 7234, 27°38'00" N, 115°16'16'' W, 791- 

 842 m, Jan. 2, 1961. 



