MARINE GAMMARIDEAN AMPHIPODA 369 



uropod 2, uropod 3 also greatly exceeding apices of uropods 1-2, 

 rami of uropod 3 elongate, subequal and nearly as long as rami of 

 uropods 1-2; gnathopods feeble; body poster odor sally carinate and 

 toothed. See Gammaridae, Oedicerotidae. 



Description. — Accessory flagellum vestigial or multiarticulate ; 

 body slender, posterodorsally carinate and toothed; rostrum poorly 

 developed; head with lateral ocular bulges; coxae short and scarcely 

 touching serially; mouthparts basic; gnathopods feeble, intermediate 

 between subchelate and simple; pereopods greatly elongate; uropod 

 3 immensely elongate as in diagnosis above and Gammaridea Key A, 

 couplet 7 (p. 107) ; telson of medium length, deeply cleft or emarginate. 



Relationship. — Uropod 3 usually falls off of preserved individuals 

 of this family as it often does on individuals of Oedicerotidae and 

 Megaluropus (Gammaridae). Some oedicerotids have uropod 3 elon- 

 gate as in melphidippids but they lack posterodorsal pleonal teeth. 

 Melphidippids may also be recognized by the lateral ocular bulges of 

 the cephalon and the very short coxae. Gammaridae with elongate 

 uropod 3 have one or more of the following exceptions to the melphi- 

 dippid pattern: inner ramus of uropod 3 shortened and scale-hke; 

 uropod 3 not exceeding apices of uropods 1-2; peduncle of uropod 3 

 shorter than rami of uropods 1-2 and not twice as long as telson or 

 urosomite 3; rami of uropod 3 much shorter than peduncle. Melphi- 

 dippids lack sexual dimorphism in the gnathopods common to most 

 Gammaridae. 



The Vitjazianidae have a short peduncle of antenna 1. 



My interpretation of Walker's description of Hornellia is that it 

 lacks the melphidippid condition of uropod 3, for he mentions the 

 medium length of the uropods and that the inner ramus of uropod 3 

 is twice as long as the peduncle; if the peduncle were of the normal 

 melphidippid length the total uropod would be two-thirds the length 

 of the body, a condition so remarkable that Walker would have 

 mentioned it. Indeed, Hornellia Walker was removed to the Gam- 

 maridae by Pillai (1957). 



The calliopiid Metaleptamphopus may belong in the Melphidippidae. 



Key to the Genera of Melphidippidae 



1. Accessory flagellum long, 2- or more articulate (fig. 1336) . . Melphidippa 

 Accessory flagellum very short, 1-articulate (fig. 133c) 2 



2. Telson cleft (fig. 133m) Melphidippella 



Telson entire, emarginate (fig. 133n) Melphisana 



