246 
GAMMARIDiE. 
AMPH1P0DA. 
NATATORIA. 
OA MM A RIDES. 
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. 
Ampjhitoe Swammerdamii. Milne Edwards, Ann. des Sci. Nat. xx. p. 378. 
Hist, des Crust, t. iii. p. 35. 
Atylus Svjammerdamii. Spence Bate, Cat. Amph. Brit. Mus. p. 136, 
pi. xxvi. f. 2. 
Dexamine Gordoniana. Spence Bate, Ann. Nat. Hist. 2 ser. xix. p. 142, 
Feb. 1857. 
Dexamine Loughrini. 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 
