DEC A POD. 1 . CORYSTIDJS. 



BRACHYURA. 



GENUS CORYSTES. LEACH. 



CANCER. Penn., Herbst. 



ALBUNEA. Fabr., Bosc. 



CORYSTES. Latreille, Leach, Edwards. 



Generic Character. External antennce very much developed, 

 longer than the carapace, setaceous, ciliated ; the basal joint 

 thick, nearly cylindrical, inserted immediately beneath the eye in 

 a hiatus of the orbits ; the second joint also nearly cylindrical, 

 bending downwards and inwards, approaching its fellow, so that 

 the third joint is articulated at right angles with it, and stands 

 forwards in contact with that of the other side this is cylindrical, 

 and twice as long as it is broad ; the remaining joints, like the 

 former, are nearly cylindrical, and fringed with hair. Internal 

 antennce folded longitudinally. External pedipalps long, narrow, 

 standing forwards as far as the origin of the internal antennae, 

 leaving an aperture between themselves and the epistome directed 

 forwards ; the third joint longer than the second, and terminating 

 forwards in a narrow and pointed process, extending beyond the 

 origin of the fourth joint, which is articulated in a notch in the 

 inner margin. Anterior legs, equal, subcompressed, with the 

 fingers deflexed ; in the male twice as long, and in the female as 

 long as the body, the remaining legs of moderate size, compressed, 

 ciliated ; the terminal articulation very long, straight and acute. 

 Abdomen in the male five-jointed, in the female seven-jointed; the 

 first and second joints visible from above, and on nearly the same 

 plane as the carapace. Carapace much longer than it is broad, 

 elliptical, with the latero-anterior margins toothed; the rostrum 

 triangular ; orbits transverse, with two fissures above. Eyes little 

 thicker than their peduncles, couching outwards and a little down- 

 wards in the orbits. 



