544 THE OCEAN WORLD. 
leather, certain plates of teeth, which are triangular, dentate, and 
white as ivory. If the shark is an adult it has in the upper as in the 
lower jaw six rows of these murderous teeth, an arsenal ready to tear 
and rend its victim. These teeth take different motions according to 
the will of the animal, and are obedient to the muscles round their 
base, by means of which it can erect or retract its various rows of 
teeth ; it can even erect a portion of any row, while the others 
remain at rest in their bed. Thus this far-seeing tyrant of the ocean 
knows how to measure the number and power of the arms necessary 
to destroy its prey: for the destruction of the weak and defenceless 
Fig. 361.—The Shark (Carcharius vulgaris). 
one row of teeth suffices ; for the more formidable adversary it has a 
whole arsenal at command. 
The eyes of the shark are small, and nearly round ; the iris of a 
deep green, the eyeball, enclosed in a transverse slit, is bluish. 
The scent of the white shark is said to be very subtle. Its fins are 
strong and rough. The pectoral fins are triangular, and much larger 
than the others, extending on each side, and giving powerful aid in 
swimming. ‘The caudal fin is divided into two very unequal lobes, 
the upper extending in a sloping direction to twice the length of the 
other. This tail is possessed of immense power, and is capable of 
breaking the limb of a robust man by a single stroke. 
During the hot season the male and female seek each other ; they 
approach the coast roving in company, forgetting their ferocity for 
the time. The eggs are hatched at several periods in the ovary, from 
which the little ones issue two or three at a time, 
