PHERUSA BICUSPIS. 
253 
AMP HIP OB A. 
NAT ATOM A. 
GA MM A R IDES. 
Specific character. First two segments of the pleon dorsally produced into 
teeth, and the posterior margin of the third segment not serrated ; fourth 
segment deeply sinuated. 
Length 2 S S inch. 
Amphithoe bicuspis. Kroyer, Giron. Amph. p. 45, pi. i. fig. 1. 
Pherusa bicuspis. Milne Edwards, Hist, des Crust, t. iii. p. 38. Spence 
Bate, Cat. Amph. Brit. Mus. p. 144, pi. xxvii. 
fig. 7. 
Pherusa cirrus. Spence Bate, Cat. Amph. Brit. Mus. p. 143, pi. xxvii. 
fig. 6. 
The head is anteriorly produced between the supe- 
rior antennae. The first two segments of the tail have 
the dorsal surface posteriorly produced into sharp cusps 
or flat teeth ; the third segment has the postero-lateral 
margin smooth— a circumstance which offers a ready 
point of distinction between this species and Atylus 
bispinosus. The eyes assume a little of the kidney- 
