DECAPODA. CANCEEID/E. 



BRACHYUBA. 



GENUS PIRIMELA. 



Cancer, Montagu. 



PiRiMELA, Leach, Desmarert, Edwards. 



Generic Character, — External antennce nearly half the length 

 of the carapace ; the basal joint short, filling a space at the inner 

 angle of the orbit ; the moveable portion inserted at its inner 

 canthus. Internal antennce lying somewhat obll({uely in their 

 cavities, which open immediately under the margin of the front. 

 External pedipalps extending forwards beyond the oral cavity, 

 and covering the epistome ; the thii'd joint sub-quadrate, emargin- 

 ate at the inner margin, about one third from the anterior angle, 

 for the articulation of the palpes. Anterior legs small, compressed ; 

 the remaining pairs of moderate length, much compressed ; the 

 terminal joint nearly straight. Carapace nearly as long as it is 

 broad, convex, with numerous sti-ongly-marked elevations ; the 

 anterior margin arched, the posterior much narrowed ; front tri- 

 dentate, the middle tooth the longest. Orbits, with two fissures 

 above. Ei/es, not thicker than their peduncles,, which are very 

 thick at the base. Abdomen, in the male, five-jointed ; in the 

 female, seven-jointed. 



Of this genus one species only is at present known. It 

 flifters from all the other Cancerida., in the circumstance 

 that the external pedipalps, instead of being- confined to 

 the opening of the oral cavity, are advanced over the 

 epistome to the antennary cavities. 



In its affinities this genus probably ap])roaches the For- 

 tunida: by the genus Carcinus ; possibly Panopaus may be 

 intermediate between them. 



