CYRTOPHIUM. 479 



.1 MPHIPODA . PODOCERIDES. 



NATATORTA. 



Genus CYRTOPHIUM. 



Cyrtophium. Dana, U. S. Explor. Exped. p. 839. Spence Bate, Ann. 



Nat. Hist. 2 ser. xix. p. 145. Cat. Amph. Brit. Mus. 



p. 278. White, Pop. Hist. Brit. Crust, p. 195. 

 Platophiwm. Dana, U. S. Explor. Exped. p. 838. 

 LcetmcUophylus. Bkuzelius, Skaud Amph. Gramm. p. 11, pi. i. fig. 1. 



Generic character. Cephalon subquadrate. Pereion dis- 

 tended. Pleon narrow. Eyes prominent. Antennae subpedi- 

 form ; inferior pair the longer. Gnathopoda subchelate ; second 

 pair much larger than the first pair. Posterior pair of pleopoda 

 rudimentary. Telson squamiform. 



In this genus the animals, when viewed from above, 

 have the head very square, the body distended to an 

 oval, while the tail is considerably narrowed, and 

 generally lies inflected against the under side of the 

 body. The eyes are prominent. The antennas are 

 subpediform, the flagella not being multi -articulate ; 

 and the inferior pair always longer than the superior. 

 The first two pairs of legs have the hands subchelate, 

 the second pair being considerably larger than the first. 

 The last two pairs of walking legs are considerably 

 longer than the others. The caudal appendages are 

 successively shorter posteriorly, the last pair being quite 

 rudimentary, and scarcely longer than the central ter- 

 minal scale. 



It will be perceived that we have united Dana's two 

 genera into one, since the only distinction that the 

 author admits between Platophium and Cyrtophium de- 

 pends upon " the respective lengths of the branches 

 belonging to the caudal appendages, the more lamellar 



