GAMMARIDEAN AMPHIPODA HI 



Bathymedon cahio, new species, lias longer posterior lobes on the 

 fifth articles of the gnathopods than does B. nepos, large terminal 

 spines on the telson, a more strongly constructed distal portion of 

 article 2 on pereopod 5 and a narrower coxa 4. 



Monoculodes Stimpson 

 Monoculodes diversisexus, new species 



Figure 51 



Diagnosis. — Rostrum short, straight, thick, not exceeding forward 

 extent of truncated lateral cephalic lobes ; eyes absent; body like Mono- 

 culodes {?) sudor, new species, having faint sculpture of pereonites, 

 pleonal epimera similar; articles 1 and 2 of antenna 1 interequal in 

 length, article 3 one third as long as article 1 ; epistome obtusely tri- 

 angular anteriorly ; gnathopods with very broad sixth articles, article 1 

 on gnathopod 1 being nearly as broad as long but on gnathopod 2 being 

 more slender, about 85 percent as broad as long, posterior lobe of article 

 5 on gnathopod 1 large, projecting slightly distalwards but not guard- 

 ing article 6, lobe on gnathopod 2 slender, turned distally, guarding and 

 projecting about halfway along article 6, article 4 of both gnathopodal 

 pairs with sharp posterodistal process ; pereopodal dactyls longer than 

 sixth articles ; telson truncate, bearing two distomeclial spines. 



?Male and some juveniles. — One male fragment having flagellum of 

 antenna 2 three times as long as articles 4 and 5 of peduncle combined, 

 instead of being subequal to peduncle as in female ; lobe on article 5 of 

 gnathopod 2 on females, males, and juveniles shorter than 7.0 mm 

 (to about 3.5 mm) shorter than on terminal adult, reaching about one 

 third along article 6; article 4 having posterodistal process poorly 

 developed or absent. 



HoLOTYPE.— AHF No. 6029, female, 8.5 mm. 



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

 1748 m, Dec. 31, 1960. 



ISIaterial. — Twelve specimens from the type-locality; stations 7234 

 (1), 7358 (3). 



EELATiONSHir. — Tliis species has broad gnathopods similar to those 

 of Monoculodes latisslmanv^ Stephensen (1931) and M. abacus J. L. 

 Barnard (1961) but M. diversisexus differs from those species by the 

 very short rostrum not exceeding the forward extent of the lateral 

 cephalic lobes. In the genus Oedlceroides Stebbing, M. diversisexus 

 bears comparison with 0. hrevirostris Schellenberg (1931) from which 

 it differs in the absence of eyes, the more strongly flexed posterior lobe 



