478 U.S. NATIONAL MUSEUM BULLETIN 271 



A few setae of pereopods 1-5 are elongate in some vitjazianids and 

 the term "fossorial" might be applied to them but other fossorial 

 families do not have a basally conjoint primary flagellum on antenna 1. 



Vitjazianids have definitive similarity to Gammaridae and Eusiri- 

 dae, from which they differ by the very short peduncle and the long 

 conjoint base of the primary flagellum on antenna 1. By evidence of 

 gnathopods and mandible, but not of telson and head the vitjazianids 

 are closely related to synopiids (tironids) and demonstrate again the 

 difficulty in defining families because of the centripetal radiation of 

 evolutionary lines around the Gammaridae. 



Key to the Genera of Vitjazianidae 



1. Gnathopod 2 subchelate; coxae of medium length; mandibular palp claviform. 



Vemana 

 Gnathopod 2 simple; coxae minute; mandibular palp linear . . . Vitjaziana 



Genera of Vitjazianidae 



Vemana J. L. Barnard 



Vemana J. L. Barnard, 1964a. 



Type-species: V. compressa J. L. Barnard, 1964a (original 

 designation) . 



Species: 2, Caribbean, bathy-abyssopelagic. 



Vitjaziana Birstein and Vinogradov 



Vitjaziana Birstein and Vinogradov, 1955. 



Type-species: V. gurjanovae Birstein and Vinogradov, 1955 (origi- 

 nal designation). 



Species: 1, N. W. Pacific, abyssopelagic. 



Incertae Sedis 



Figure 173 



Didymocheila K. H. Barnard 



Didymocheila K. H. Barnard, 1931; 1932. 



Type-species: D. spongicola K. H. Barnard, 1931 (original desig- 

 nation) ; 1932. 



Having all characteristics of Lysianassidae except article 3 of 

 gnathopod 2 not elongate and article 6 strongly elongate, gnathopods 



