GAMMARELLA. 329 



A MPHIPODA . GA MMARWES. 



NATATOBIA. 



Genus GAMMARELLA. 



Gammarella. Spence Bate, Ann. Nat. Hist. 2 ser. xix. p. 143. Cat. 



Aniph. Crust. Biit. Mus. p. 179. White, Hist. Brit. 



Crust, p. 181. 

 Gammarus part. Dana, U. S. Explor. Exped. p. 956. 



Generic character. Superior antennae furnished with a 

 secondary appendage. Gnathopoda very unequal in size in the 

 male, subchelate. Posterior pair of pleopoda unibranched. 

 Tel son single cleft. 



The superior antennas in this genus are longer than 

 the inferior, and furnished with a secondary appendage. 

 The hands of the first two pairs of legs are subchelate. 

 The caudal appendages have their branches short, the last 

 pair are furnished with but a single branch. The central 

 tail-piece is single, but divided at the apex. 



This genus forms a curious link between the family 

 OrchestiidaBf and the subfamily Gammarides, possessing, as 

 it does, the superior antennae of Gammarus, and caudal 

 appendages similar to those of Orchestia. It moreover 

 appears to differ from Crangonyoc only in having the 

 second pair of hands in the male larger than the first. 



