DECAPOD A . CA NCEEIDM. 



BRACHYUBA. 



GENUS PIBIMELA. 



CANCER, Montagu. 



PIRIMELA, Leach, Desmarert, Edwards. 



Generic Character. External antennae 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 antennae, lying somewhat obliquely 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 third 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 strongly-marked elevations ; the 

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

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

 above. Eyes, 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 

 differs 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 approaches the Por- 

 tumdce by the genus Carcinm ; possibly Panop&w may be 

 intermediate between them. 



