MEGAMCERA OTHONIS. 



AMPHIPODA. 



NATATORIA, 



405 



GAMMA RIDES. 



MEGAMCERA OTHONIS. 



Specific character. Posterior and inferior margins of the third segment of 

 the pleon serrated. Inferior margins of the coxa? of the three anterior pairs 

 of legs serrated. Gnathopoda subequal. Propoda ovate. 



Length A inch. 



Gammarus Othonis. 



Megamcera Othonis. 



Edwards, Ann. des Sci. Nat. t. xx. p. 373, pi. x. 



fig. 11. Hist, des Crust, t. iii. p. 50. Spence 



Bate, Rep. Brit. Assoc. 1855, p. 59. Ann. Nat. 



Hist. 2 ser. xix. p. 144. White, Hist. Brit. Crust. 



p. 184. 

 Spence Bate, Cat. Amph. Brit. Mus. p. 227, pi. 



xxxix. fig. 8. 



The animal is long ; and has the inferior half of the 

 posterior margin as well as the posterior half of the 

 inferior margin of the third segment of the tail serrated. 

 The eyes are round and black. The superior antennae 

 are about one-third of the length of the animal ; and the 

 peduncle is as long as the fLagellum, this latter portion 

 varies from fourteen to twenty-five articuli, and the 

 secondary appendage, which is short, from two to three. 

 The inferior antennae are about one-third shorter than 

 the superior ; the flagellum is not half the length of the 



