114 U.S. NATIONAL MUSEUM BULLETIN 2 60 



Monocidodes necopinus, new species 



Figures 53, 54 



Diagnosis. — Rostrum small, slender, straight, acute, reacliing half- 

 way along article 1 of antenna 1 ; lateral cephalic lobes broad, obliquely 

 truncated, not defined anteroventrally from remainder of head ; eyes 

 absent; articles 1 and 2 of antenna 1 equal to each other in length, 

 article 3 about one third as long as article 2 ; epistome broadly rounded 

 anteriorly; gnathopods having sixth articles of medium expansion, 

 l^osterior margins much shorter than palms, posterior lobes of fifth 

 articles of medium length but extending full length of posterior mar- 

 gins of sixth articles and guarding them, fourth articles scarcely pro- 

 duced posterodistally, gnathopod 2 with slightly narrower and longer 

 lobe than gnathopod 1; pereopodal dactyls at least as long as their 

 sixth articles; all pleonal epimera rounded posteroventrally ; telson 

 truncate, armed with two very stout, short terminal spines. 



Remarks. — Mouthparts differ in so many details from those of M. 

 carinatus Bate (see Sars, 1895, pi. 105) that they are figured herein; 

 they have the appearance of those of Oediceropsis hrevicomis Lilje- 

 borg (see Sars, 1895, pi. 114). 



HoLOTTPE. — AHF No. 6019, male, 6.7 mm. 



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

 1748 m, Dec. 31, 1960. 



IMaterial. — Seven specimens from the type-locality. 



Relationship. — Species of M onoculodes rarely lack eyes, only M. 

 latissimaniis Stephensen (1931), M. coecus Gurjanova (see 1951) and 

 M. abacus J. L. Barnard (1961) having been described as anoculate. 

 The rostrum of M. necopimis is unusually small and slender, being 

 matched only by M. lathshnanus and M. minutus Gurjanova (see 

 1951). M onoculodes necopinus differs from M. latissimanus in the 

 less strongly expanded hands of the gnathopods and the longer pos- 

 terior lobes of the fifth articles. The gnathopods of Monoculodes 

 abacus J. L. Barnard are similar to those of M. latissimanus. The 

 new species differs from M. tninutus in the absence of eyes, the presence 

 of large telsonic spines, the shorter posterior margin of article 6 and 

 the shorter posterior lobe of article 5 on gnathopod 2. 



Monoculodes necopinus differs from its sympatriot, 31. emarginatu^ 

 J. L. Barnard (1962d) , in the truncated telson having two large spines 

 (by contrast to a spineless emarginated telson), the absence of eyes, 

 the smaller rostrum, and the more strongly truncated lateral cephalic 

 lobes. It differs from M. perditus J. L. Barnard (1966a) in its shorter 

 rostrum, absence of eyes and the occurrence of large spines on the 

 telson. 



