72 
GAMMARIDJI. 
AM PH IPOD A 
L YSIA NA SSI DES. 
NAT ATOM A. 
a. First pair of gnathopoda strong ; second pair feeble and 
imperfectly cheliform. 
Genus— LYSIANASSA. 
Lysianassa, Edwards, Ann. des Sc. Nat. t. xx. Hist, des Crust, t. iii. 
p. 20. Dana, U. S. Explor. Exped. p. 908. 
Generic character. Superior antennae very short, stouter than 
the inferior, appendiculate. First pair of gnathopoda not sub- 
cheliform. Second pair imperfectly developed, but long, mem- 
branous, and subchelate. Telson single, squamiform, entire. 
This genus may be distinguished by its short upper 
antennae being very stout near the head, and suddenly 
reduced in size at the base of the flagellum, which is 
very short, and carries a secondary appendage. The 
inferior antennae are more slender and often longer than 
the superior. The mandibles are furnished with a 
jointed appendage, and armed with a sharp, smooth, 
cutting edge, carrying a stout tubercle upon the anterior 
margin. The pair of foot-jaws have large squamous pro- 
cesses attached to the third and fourth joints. The first 
pair of limbs are not formed into a claw, but terminate 
in a straight finger, which imperfectly bends upon the 
hand. The second pair are feeble and very long : this 
latter circumstance is due to the great length of the 
third joint, which, in most of the animals of this Order, 
is very short. The coxae of the four anterior pairs of 
limbs are deeper than the segments of the body to 
