SHARKS. 



301 



there are usually two dorsals, two large pectorals, 

 two ventrals with (in the males) two large ap- 

 pendages at their inner edge, an anal, and a 

 caudal of two unequal lobes, as before described 

 in the Sturgeons. The body and fins are covered 

 with a hard leathery skin, almost always rough 





t 



WHITE SHARK. 



to the touch if the hand be passed from the tail 

 upwards. This roughness arises from the pre- 

 sence of small angular spiculce of crystalline 

 appearance, imbedded in the skin, and fits the 

 skin and fins of various species to be used for 

 polishing cabinet-work. In some species the 

 skin is studded with curved spines. 



