246 



GAMMARID.E. 



AMPHIPODA. 



NATATORIJ. 



GAMMARIDES. 



ATYLUS SWAMMERDAMII. 



Specific character. Pereion and pleon smooth. Fourth segment of the 

 pleon having a deep central dorsal sinus, and ])osteriorly elevated into a 

 strong dorsal tooth. 



Length \ inch. 

 A mphitoS Swammerdamii. 



A tylus Swammerdamii. 



Dexamine Gordoniana. 



Dexamine Lowjhini. 



Milne Edwards, Ann. des Sci. Nat. xx. p. 378. 



Hist, des Crust, t. iii. p. 35. 

 Spence Bate, Cat. Amph. Brit. Mas. p. 136, 



pi. xxvi. f. 2. 

 Spence Bate, Ann. Nat. Hist. 2 ser. xix. p. 142, 



Feb. 1857. 

 Spence Bate, Cat. Amph. Brit. Mus. p. 132, 



pi. xxiv. fig. 3. 



The head of the animal is anteriorly produced into a 

 small rostrum. The body is smooth and even, except 

 the fourth segment of the tail, which has a deep 

 central dorsal sinus, the anterior wall of which is pro- 

 duced into a sharp tooth, and the posterior portion of 

 the segment has the dorsal medial line carinated and 

 elevated into a strong tooth. The eyes are oval. The 



