140 CRUSTACEA. 



Typhis (Bisso). Second antennge folding on 

 themselves so as to form three or four elbows; first 

 joint of fifth and sixth feet forming great oval 

 plates, concealing all the others. 



T. monoculoides. Fig. 252 ; mag. -f-. 

 nolens. 



Tribe III. Gammaracea. 



Body depressed ; epimera very 

 small or obsolete ; abdomen straight, 

 normal ; three last pairs of false feet 

 tipped with swimming-plates ; an- 

 tennge foot-shaped Corophiada. 



Body much compressed ; epimera 

 very large, scale-like, and encasing 

 the bases of the first four pairs of 

 feet ; posterior extremity formed for 

 leaping. 



Superior antennae longer than the 

 footstalk of the inferior, and much 

 longer than the head; mandibles 

 carrying long palps ; antennae lash- 

 like Gammaridce. 



Superior antennae much shorter 

 than footstalk of inferior, and 

 scarcely longer than head ; mandi- 

 bles without palps Orchestiadte. 



Family I. Corophiad,e< 



Cerapus (Say) . Second feet fanged ; fang two- 

 jointed; all the antennge without many-jointed 

 lashes at the tip. 



C. pelagicus. C. Whitei. Fig. 253 ; mag. f . 



falcatus. 



