216 NATURAL HISTORY. 
to contain nine million of eggs. Fishes being thus pro- 
lific, societies of them, or shoals, as they are called, are 
often immense in multitude. They would be too abund- 
ant were their number not kept down by various causes. 
Many of the eggs are destroyed, and then of the young 
fish so many are eaten by other fish, and are killed in va- 
rious ways, that few of them comparatively come to ma- 
turity. 
364. Some fishes present a strong contrast to all this 
in the number of their young. This is the case with that 
rapacious fish, the Shark, thus illustrating the Divine wis- 
dom and benevolence. It produces but two eggs. The 
egos of some species of the Sharks are great curiosities. 
They are of firm texture, and of a purse-like shape, with a 
long tendril extending from each corner of it, as seen in 
Fig. 168. These tendrils, coiling around seaweed or any 
Fig. 168, me of Shark. 
other substance, serve to anchor the egg securely. The 
purse is thin at the end where the head of the young fish 
is, and when it is in a fit state to come out, it breaks its 
way through this end. Some other fishes lay similar 
eggs. They are sometimes picked up by the sea-shore, 
and are called Mermaids’ Purses. 
365. Fishes supply quite a large portion of the food of 
the human family. An immense amount of capital is 
employed in carrying on the fisheries, and in some quar- 
ters a large part of the population are engaged in them. 
