388 
GAMMA. RIM. 
AMPHIPODA, GAMMARJDES. 
NATATORIA , 
Specific character. Very much like G. locusta. A few slender cilia mixed 
with the spines on the dorsal surface of the fourth and fifth segments of the 
pleon. Eyes reniform, formed of minute black dots. Secondary appendage 
of the superior antennae slender, rather short, 3-4 jointed. Posterior pair 
of pleopoda much longer than the preceding pair ; having the rami subequal, 
subfoliaceous, and with the margin ciliated. Upper antennae rather longer than 
the inferior ; peduncle of the inferior much longer than that of the superior. 
Length of male ^ inch. 
Cancer pulex. Linnaeus, Syst. Nat. 1055 ? Krebsformiger Wasser- 
wurm, Frisch, Ins. vii. p. 26, fig. 18. 
De Geer, Memoires, vii. p. 525, t. 33 (certe). 
Pennant, Brit. Zool. iv. 21. 
Squilla pulex. 
Astacus pulex. 
