54 
GAMMA RULE. 
A MPHIP OB A . S TEG 0 CEP II A LIDES. 
NAT ATOM A. 
Specific character. Second pair of gnathopoda haying the propodos twice 
as long as broad, palm oblique, smooth, slightly convex, defined by a very 
obtuse angle armed with two sharp short spines. 
Length, of an inch. 
Cancer ( Gammarus ) monoculoides , Montagu, Trans. Linn. Soc. vol. xi. p. 4, 
pi. ii. fig. 3. 
Montagna monoculoides , Spence Bate, Rep. Brit. Assoc. 1855, 
p. 57. Synop. Brit. Amph. Ann. Nat. 
Hist. 1857, xix. 137. Cat. Brit. Mus. 
p. 55, pi. viii. fig 4. 
Typhis (1) monoculoides , Milne -Edwards, Ann. Sci. Nat. t. xx. 
Aug. 1830. White, Cat. Brit. Crust, 
in Brit. Mus. 1850, p. 58. Gosse, 
Mar. Zool. p. 140, fig. 252. 
The head produced anteriorly into a small depressed 
rostrum. The hack smooth. The eyes are round, and 
of a red colour. The superior antennae have each joint 
of the peduncle successively reduced in size, the flagellum 
