THE SKATE. 41 



In R. batis the angle of the extremity of the snout is acute, and the 

 lateral or pectoral angle slightly so : in R. clavata and R. maculata 

 the angle of the snout is obtuse and the pectoral angles nearly right 

 angles. 



55. The immense pectoral fins, of a triangular shape, 

 the bases of the triangles extending from the anterior ex- 

 tremity of the snout to within a short distance of the base 

 of the tail, and their apices forming the lateral angles of the 

 rhomboidal body. 



56. The pelvic fins, each of which lies in the angle 

 between the posterior end of the corresponding pectoral fin 

 and the root of the tail, and consists of two lobes, an ante- 

 rior outwardly-directed narrow one, and a posterior broader 

 one, produced backwards, parallel with the tail. 



57. In the male, the claspers, elongated organs, each 

 presenting a groove along the outer edge, and strengthened 

 by a cartilaginous skeleton which projects into the cavity 

 of the organ in the form of sharp plates of various shapes. 



58. The dorsal fins, two small median lobes near the 

 posterior end of the tail. 



59. The caudal fin, a still smaller lobe, quite at the 

 extremity of the tail. 



60. The characters of the integument : it is tough and 

 strong ; greyish brown on the dorsal, white or grey on the 

 ventral side : in certain parts it is quite smooth and devoid 

 of scales, but in others is roughened by minute asperities or 

 by well-marked spines, both being the exposed portions of 

 the placoid scales, each of which consists of a button- 

 like bony base imbedded in the derm, and of a thorn-like 

 enamelled portion, which projects through the epiderm on 

 to the surface of the body : these scales are best made out 

 by dissecting out one of the larger ones. 



In R. batis the dorsal integument is dark olive-green or brown, 

 the ventral integument dark grey, with minute black dots marking the 





