154 CRUSTACEA. DECAPODA. 



tubercular, dentated, and almost crested ; all the other feet 

 terminating in fins. 



M. victor, Lat. Shell whitish, with minute scattered red spots ; a 

 very strong spine on the exterior side of the forceps ; front bi- 

 dentated. 15 lines long. Inhabits Indian seas Lat. Gen. i. 42. 



Gen. 21. ORITHYIA, Lat. Cancer, Herbst. 

 Exterior antennas shorter than the intermediate ones ; legs all 

 placed in the same horizontal line ; forceps thick, equal ; the 

 three following pairs terminated by a straight and pointed 

 claw, and the fifth by a compressed, oval, and ciliated joint ; 

 eyes on a slender and cylindrical peduncle. 



O. mamillaris, Fab. Shell tubercular, with three spines on each 

 side, the front projecting, with live teeth ; forceps spinous ; two 

 reddish spots on the back. 15 lines long. Inhabits Indian seas. 

 Herbst, pi. 18, fig. 101. 



Gen. 22. COUYSTES, Lat. Cancer, Herbst. 

 Exterior antennae longer than the body, setaceous, ciliated in 

 two rows ; exterior feet-jaws with the third joint longer than 

 the second ; eyes pedunculated; shell oval, longer than broad ; 

 anterior feet large, equal, twice longer than the body in the 

 male, and the length of the body in the female, with forceps ; 

 the other feet terminated by a furrowed claw. 



C. dentata, Lat. (C. Cassivelaunus, Pen.) Shell granulated, cre- 

 nated behind ; front bifid, the sides tridentate. Inhabits British 

 coasts Pen. Brit. Zool. iv. pi. 7- 



Gen. 23. LEUCOSIA, Fab. Cancer, Herbst. 

 Antennae small, approximated, inserted between the eyes ; eyes 

 very small ; shell rounded oval, very convex, solid, with the 

 sides deeply canaliculated ; anterior pair of legs thicker than 

 the others, and with forceps. 



L. craniolaris, Lat. Shell smooth above, depressed on each side 

 before, with the anterior margin crenulated ; front slightly advan- 

 ced, tridentate ; arms warty. Indian seas Herbst, pi. 2, fig. 17- 



Gen. 24. HEPATUS, Lat. 



Exterior antennae very small ; second joint of the exterior feet- 

 jaws pointed at the summit ; shell broader than long, rounded 

 before and narrowed posteriorly, with the lateral borders den- 

 tated ; forceps compressed and crested. 



H.fasciatus, Lat. Shell slightly convex, the anterior lateral mar- 

 gins finely crenated ; colour yellowish, the shell and legs banded 

 with red ; forceps blackish. American seas. Herbst, pi. 38, fig. 2. 



FAMILY IV. CBYPTOPODA. 



Posterior angles of the shell dilated and vaulted ; forceps very 

 large, compressed and crested ; shell almost triangular. 



