120 
GAMMARIDiE. 
A MPHIPODA . L YSIA NASS IDES. 
NAT ATORI A. 
Specific character. Inferior antennse one-third the length of the animal. 
First pair of gnathopoda having the dactylos developed into a thick brush of 
short hair. Fourth segment of the pleon having on the dorsal surface a deep 
notch. 
Length, ^ inch. 
Callisoma crenata. Spence Bate, Cat. Ampin Brit. Mus. p. 85, pi. 
xiv. fig. 5. 
Scopelocheirus crenatus. Spence Bate, Brit. Assoc. Rep. 1855, p. 58. 
Synop. &c., Ann. Nat. Hist. xix. 138 (1857). 
White, Hist. Brit. Crust, p. 167. 
This species is very round and smooth, and rolls itself 
up almost into a ball. The head is small, and anteriorly 
produced into a minute flat rostrum, which is merely a 
projecting portion of the shin, extending horizontally with 
the top of the head. The antero-inferior angle projects 
as far forwards as the extremity of the rostrum. The 
eyes are small and reniform, showing black spots on a 
