STALK-EYED CRUSTACEA 455 



I. Benthesicymus pleocanthus. 



Benthesicynius pleocantJnts . . . Spence Bate. 



Surface membranous. Rostrum pointed. Crest armed 

 with two teeth, the anterior of which is the smaller. 

 Cervical fossa clearly defined, but not deep. Abdomen 

 with the posterior segments laterall)- compressed, and the 

 dorsal surface of the fifth segment posteriorly produced 

 in the median line to a laterally compressed tooth that 

 nearly equals the segment in length. The sixth segment 

 is deep, and carries a distinct but not a high ridge in the 

 median dorsal line. The telson tapers to a point, is 

 smooth at the sides, and quite half the length of the lateral 

 wing of the swimming organ. 



Range. — West Indies, Philippine Isles, North Pacific. 



Division III. Phyllobranchiata. 



Pliyllobrancliiata .... Spence Bate. 



The gill plumes are developed in the form of broad 

 foliaceous plates attached to a central stalk. 



Group Normalia (Spence Bate). 



The three posterior pairs of legs are never armed with 

 pincers. 



Tribe I. Polycarpidea. 

 Tribe II. Monocarpidea. 



Synopsis of the Tribes. 



A. The second pair of legs 

 slender ; the fifth joint is divided 

 into a number of small joints. — 



r D 7 J.- J \ Polycarpidea. 



[Folycarpiaea.) 



