THE SHARK. 45 
« 
and which opens a Kttle to let the water out. 
But sharks, and some other fishes, have their 
gills fixed within little pouches, which open out- 
wards through holes that have no coverings. 
6. Fishes feed upon other fishes, and many of 
them are good food for us too. But the shark is 
Shark — turned with mouth upwards to seize prey. 
fierce enough to seize and eat us if we give it the 
chance. Men dread it because it is so large and 
strong, and because of its fearful-looking mouth, 
which is set with rows of sharp, white teeth. 
7. The shark can raise its teeth upright, or let 
them lie at rest, just as it needs. It uses those 
