170 U.S. NATIONAL MUSEUM BULLETIN 2 60 



Type-locality.— Station 7229, 27°54'25" N, 115°40'00" W, 1720- 

 1748 m, Dec. 31, 1060. 



;^L4TERIAL. — Five specimens from the type-locality. 



Remarks. — Only the truncate coxa 3, tlie apparently larger tooth of 

 l^leonite 5 and the slightly stouter fourth articles of pereopods 3-5 are 

 of any quantitative value in erecting this subspecies. Coxa 6 has a 

 longer posterior lobe than shown by Pirlot for P. I. Ionga\iudafus in his 

 view of the dissected appendage, but his whole-mount drawing shows 

 the lobe to be present. 



The head of P. houvieri Chevreux (1895, and see J. L. Barnard, 

 19Glb) is very different from that of the material at hand because it 

 has a nasiform rostrum projecting apically and ventrally; and P. 

 bouvieri has very short, ornamented pereopodal dactyls. Pseudotiron 

 golens J. L. Barnard (1962a) has distinctive coxae, medium-sized 

 pereopodal dactyls, rather quadrate pleonal epimera, almost no dorsal 

 tooth on pleonite 4 and a short head. 



The accessory flagellum of P. I. greteus is 3-articulate and males 

 have the base of the flagellum of antenna 1 unsegmented. Two of the 

 specimens are females and differ from the male only in the segmented 

 flagellar base. 



One of the females has a f oregut entirely full of silt particles. 



Pseudotiron pervicax, new species 



Figure 84 



Diagnosis. — Anterodorsal portion of head not strongly extended 

 forward, intermediate between P. longicaudatus Pirlot (1934) and 

 P. houvieri Chevreux (1895, and see J. L. Barnard, 1964b), deflexed, 

 rostrum acute but broad, essentially defined below by deep, rounded 

 incision on anterior keel, latter projecting strongly in front of lateral 

 cephalic lobes, latter quadrate; upper lip separated from anterior 

 epistomal keel by strong notch ; coxa 1 beveled anteroventrally, coxa 3 

 with posteroventral lobe poorly developed, subacute, coxa 4 not attenu- 

 ated as in P. longicaudatus; dactyls of pereopods intermediate in size 

 between those of P. longicaudatus and P. houvieri but complexly armed 

 as in P. houvieri; pereopods 3-5 very short, fifth articles shorter than 

 fourth, sixth even shorter than fifth; article 2 of pereopod 5 strongly 

 expanded posteriorly, with posteroventral and posterodorsal margins 

 symmetrically rounded (in contrast to P. long icaudatus) ; pleonites 

 1-3 each with small dorsal tooth, serrations on posterodorsal margins 

 obsolete, pleonite 4 with large tooth masked by chitinous lamina, tooth 

 of pleonite 5 very long, reaching to end of pleonite 6, latter short in 

 comparison with P. longicaudatus; pleonal epimeron 1 rounded pos- 

 teroventrally, 2 and 3 with slightly convex posterior margins and small 



