CALAPPA. CRUSTACEA. 155 



The animals of this family withdraw their feet within the vaulted margin of the 

 shell when at rest, with the exception of the large claws. None of the tarsi are fin- 

 shaped. 



Gen. 25. CALAPPA, Fab. Cancer, Lin. 



Exterior antennas short, the two interior folded under the hood ; 

 third joint of the exterior feet-jaws pointed ; forceps unequal, 

 very large, compressed ; the other feet short and simple ; 

 shell short, convex, broadest posteriorly, and vaulted for the 

 reception of the feet in repose. 



C. granulata, Fab. Shell warty, marked with four longitudinal su- 

 tures, and on each side before its dilation seven teeth ; front 

 bidentate ; flesh-coloured, with spots of carmine red. 2J inches 

 long, 3J broad. Mediterranean sea. Herbst, pi. 12, fig. 75, 76- 



Gen. 26. (ETHRA, Leach. Cancer, Lin. 

 Third joint of the exterior feet-jaws almost square ; eyes sepa- 

 rated by the projection in front, and on short peduncles ; 

 shell flattened, raised into knobs on the back ; the two anterior 

 feet with compressed and crested hands. 



(E. depressa, Lam. Shell elliptical, transverse, with the lateral bor- 

 ders rounded, and marked with plicated teeth. Inhabits Indian 

 seas. Herbst, pi. 53, fig. 4, 5. 



FAMILY V. TRIGONA. 



Shell triangular or subovoid, with the anterior extremity nar- 

 rowed and pointed ; claws often larger in the males than in 

 the females. 



Gen. 27. PARTHENOPE, Fab. Cancer, Lin. 



Exterior antennae extremely short, the first two joints very thick; 

 third joint of the exterior feet-jaws truncated and notched to- 

 wards the extremity of the internal side ; forceps unequal, very 

 large, with the joints angular and covered with tubercles, ru- 

 gosities, and points ; the other feet rugous and narrowed to- 

 wards the extremity ; shell rhomboidal, excessively irregu- 

 lar, prolonged into a beak before and into sharp angles la- 

 terally ; eyes large, on short peduncles, and lodged in lateral 

 grooves. 



P. horrida, Fab. Shell irregular, with large impressed tubercles 

 and rugous furrows ; legs spinous ; hands and wrists verrucose ; 

 abdomen and breast carious ; colour reddish. Inhabits Asiatic 

 ocean. Leach, Zool. Mis. ii. pi. 98. 



Gen. 28. EUIIYNOME, Leach. 



External antennae rather long, with the first joint shorter than 

 the second ; shell verrucose, terminated anteriorly by a bifid 

 rostrum ; eyes distant, thicker than their peduncle ; exterior 

 feet-jaws with the third joint nearly square and notched towards 



