98 U.S. NATIONAL MUSEUM BULLETIN 2 60 



UKOPOD 3 NOT GROSSLY EXTENDING BEYOND UKOPODS 1 AND 2 ; bodj Seg- 

 ments not carinate. 



Type-species. — Halicreion latipes G. O. Sars. 



Remarks. — The capitalized portions of the diagnosis form the most 

 important combination of characters. 



Key to the Species of Aceroides 



1. Article 4 of gnatliopod 1 with large posterodistal process nearly equaling 



that on article 5 2 



Article 4 of gnathopod 1 lacking posterodistal process or with short acute 

 process much smaller than that on article 5 4 



2. Length of lobe on article 5 of gnathopod 2 greatly exceeding posterior margin 



of article 6, palm longer than posterior margin . A. synparis J. L. Barnard 



Length of lobe on article 5 of gnathopod 2 equaling posterior margin of article 



6, palm shorter than posterior margin 3 



3. Articles 4-5 of pereopods 1-2 weakly expanded, article 2 of pereopod 3 unex- 



panded and article 6 not longer than 5 A. edax, new species 



Articles 4-5 of pereopods 1-2 strongly expanded, article 2 of pereopod 3 ex- 

 panded and article 6 much longer than 5 ... A. limicola K. H. Barnard 



4. Posterior process on article 5 of gnathopod 1 blunt, subrounded, scarcely 



turned distalwards and not guarding article 6 5 



Posterior process on article 5 of gnathopod 1 subacute, turned distalwards and 

 guarding most of posterior margin of article 6 6 



5. Palm of gnathopod 2 shorter than posterior margin of article 6, process of 



article 5 extending one third along posterior margin of article 6, article 4 of 

 gnathopods with small, acute process, article 2 of mandibular palp straight. 



A. callida, new species 

 Palm of gnathopod 2 longer than posterior margin of article 6, process of 

 article 5 extending more than halfway along posterior margin of article 6, 

 article 4 of gnathopods with obsolescent, blunt process, article 2 of man- 

 dibular palp curved A. kobjakovae Bulycheva 



6. Dactyls perfectly fitting gnathopodal palms, hands expanded distally, process 



on article 5 of gnathopod 1 stout, article 3 of mandibular palp tapering 



symmetrically, ovately elongate A. latipes (Sars) 



Dactyls overriding gnathopodal palms, hands unexpanded or slightly taper- 

 ing distally, process on article 5 of gnathopod 1 very thin, article 3 of man- 

 dibular palp slender but subfalciform A. sedovi Gurjanova 



Aceroides callida, new species 



Figure 44 



Diagnosis. — Rostrum almost completely absent, front of head 

 weakly bulbous, with slightly erect anterodorsal ridge ; lateral cephalic 

 lobes rather narrow and projecting, but apically rounded; eyes absent; 

 [antenna 1 missing;] antenna 2 slender, short, gland-cone small but 

 sharply distinct; epistome rounded anteriorly; mandibular palp 



