MONSTRILLA AND THE CYMBASOMATIDZ. 121 
CORYCHIDA. 
(Thorell, G. 8. Brady.) 
Body subpyriform. 
Abdomen elongated, much 
narrower than the ceph- 
alothorax. 
Anterior antenne 5—7 
jomted; alike in both 
sexes, short. 
Posterior antenne simple, 
3—4 jointed, forming a 
strongly clawed prehen- 
sile hand. 
Mandibles, maxille, and 
first pair of foot jaws 
present, but destitute (or 
nearly so) of palps. 
Posterior foot jaws pre- 
hensile, and in the 
male powerfully clawed. 
First four pairs of feet 
adapted for swimming, 
2 branched. 
Fifth pair of feet rudimen- 
tary alike in both sexes, 
rarely absent, 
CYMBASOMATIDA. 
(I. C. Thompson.) 
Body elongated, boat- 
shaped. 
Abdomen scarcely narrow- 
er than cephalothorax. 
Anterior antenne 4— 6 
jointed; different in the 
sexes, the male on both 
sides being thickened 
and geniculated. 
Posterior antenne and 
enathites entirely ab- 
sent. Rudiments of 
enathites present in 
larval specimens. 
Mouth circular, at end of 
cylindrical process on 
ventral surface of cepha- 
lon, and leading into a 
short pharynx ; remain- 
der of digestive tract 
aborted. 
First four pairs of feet 
adapted for swimming, 
2 branched. 
Fifth pair of feet rudi- 
mentary in both sexes, 
