154 STALK-EYED CRUSTACEA 



17. Pilumnus. 



Piliivinus .... Leach, Milne Edwards, Miers. 

 Acanthus .... Locking^ton. 



Parapihivinus \ 

 Eiipilunnius J 



Kossmann. 



The carapace is longitudinally convex, a little broader 

 than long, with the regions distinctly defined ; it is thickly 

 covered with hair on the dorsal surface, extending over 

 the legs, not lobulated ; the antero-lateral margins, regu- 

 larly bowed, are shorter than the postero-lateral margins, 

 and are normally armed with short spines in place of 

 teeth. 



The front is rather narrow ; its anterior margin has 

 spines or is granulated, and is divided into two lobes by 

 a median emargination ; outside each there is usually a 

 small lobe or rounded tooth. 



The orbital margins are sometimes entire, sometimes 

 have spines. The eyes are of moderate length. The 

 basal antennal joint is short, slender, and scarcely reaches 

 the infero-lateral frontal process, or sometimes falls short 

 of it ; the next joint lies within the interior orbital hiatus. 

 The fourth joint of the external maxillipedes is distinctly 

 truncated, and in typical specimens is not narrower than 

 the third joint. The legs of the first pair arc moderately 

 robust and usually unequal, with the fourth joint short 

 and trigonous; the fifth and palm are more or less granu- 

 lated, and spinuliferous on the superior margin and 

 exterior surface ; fingers, distal!}- acute or subacute, are 

 dentated on the inner margins ; walking legs of moderate 

 length, slightly compressed, but not carinated, fourth to 

 sixth joint sometimes armed with spinules ; last joint 

 slender, styliform, and nearly straight. 



