246 



GAMMARID.E. 



AMPH1P0DA. 

 NATATORJA. 



GAMMAR1DES. 



ATYLUS SWAMMERDAMTI. 



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

 pleon having a deep central dorsal sinus, and posteriorly elevated into a 

 strong dorsal tooth. 



Length \ inch. 

 A mphitoe Swammerdamli. 



Atyhcs Swammerdamli. 



Dexaminc Gordoniana. 

 D ex amine Louyhrini. 



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



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

 S pence Bate, Cat. Am ph. Brit. Mus. 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 



