MARINE GAMMARIDEAN AMPHIPODA 145 



Pleonexes Bate 



Anisopus Templeton, 1836 (homonym, Diptera). 

 Pleonexes Bate, 1857a. 



Type-species: P. gammaroides Bate, 1857a (monotypy). See Sars, 

 1895. 



Antenna 1 lacking accessory flagellum; mandible with palp; 

 gnathopods large, subch elate, gnathoped 2 equal to or larger than 1 ; 

 article 6 of pereopods 3-5 apically widened and suhprehensile (Ampithoe) ; 

 outer ramus of uropod 3 with two hooks; telson with apical pair of 

 reverted, elongate, cornijied . processes (Ampithoe). Species: 3, N.E. 

 Atlantic, New Zealand, littoral. 



Sunamphitoe Bate 



Sunamphitoe Bate, 1857a. 



Type-species: Amphithoe pelagica Milne Edwards, 1830 (desig- 

 nated by Chevreux andFage, 1925). See Sars, 1895 (as S. conformata). 



Antenna 1 lacking accessory flageUum; mandible lacking palp; 

 gnathopods large, subchelate, gnathopod 2 equal to or larger than 

 1; article 6 of pereopods 3-5 not apically widened; outer ramus of 

 uropod 3 with two hooks. Species: 2, N.E. Atlantic, epipelagic. 



Anamixidae 



Figure 62 



Diagnosis. — ^Mandible, lower lip, and maxillae absent; buccal 

 regions with ventrally projecting keel; outer plates of maxillipeds 

 absent, inner plates small, fused together; coxa 1, when present, 

 hidden by the shield-like coxae 2-4; telson entire. See Leucothoidae, 

 Amphilochidae, Cressidae, Sebidae, Thaumatelsonidae. 



Description. — ^Body smooth, lacking dorsal processes; mouth- 

 parts aberrant as in diagnosis; accessory flagellum absent; gnathopod 

 1, when present, small and complexly chelate, having a chelate 

 process on article 5, articles 6 and 7 (when present) together forming 

 dactyl; gnathopod 2 immense, article 5 forming a false chela but 

 articles 6 and 7 large, and article 7 alone forming the true dactyl; 

 uropod 3 with styliform rami as long as the elongate peduncle; telson 

 entire. 



Relationship. — The Leucothoidae bear mandibles and maxillae. 



Key to the Genera of Anamixidae 



1. Gnathopod 1 present Anamixis 



Gnathopod 1 absent Paranamixis 



