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 
Ludal of two unequal lobes, as before described 
in the Sturgeons. The body and fins are covered 
with a hard leathery skin, almost always rough 
WHITE SHARK. 
to the touch if the hand he 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. 
