208 GAMMARIDJ;. 



A MPHIPODA . PHOXIDES. 



NATATORIA. 



Genus PH^DRA. 



Pkcedra. SPENCE BATE, Quarterly Journal of Gteol. Soc. 1858, p. 137. 

 Cat. Amph. Brit. Mus. p. 119. 



Generic character. Cephalon produced anteriorly. Seg- 

 ments of the pereion short, of the pleon long. Superior an- 

 tennae shorter than the inferior, furnished with a secondary 

 appendage. Posterior pair of pleopoda considerably elongated, 

 biramous. Telson simple or notched. 



THE head is anteriorly produced, but not to so great 

 an extent as in some of the preceding genera. The 

 segments of the body are remarkably short, whilst those 

 of the anterior half of the tail are extremely long. 

 The eyes of the type were not observed. The superior 

 antennae are shorter than the inferior, and rather more 

 robust ; they are furnished with a secondary appendage. 

 The coxae of the legs are small. The last three pairs of 

 caudal appendages are double-branched, the branches of 

 each pair respectively being subequal, those of the last 

 pair being considerably elongated. The central tail-piece 

 is squamiform or notched. 



This genus is founded on imperfect specimens. 



