54 
COMPARATIVE ZOOLOGY. 
fore-legs, crushes it between its thighs, which are armed 
with spines, and then delivers it up to the jaws for masti¬ 
cation. All Arthropods move their jaws horizontally. 
The back-boned animals generally apprehend food by 
means of their jaws, of which there are two, moving ver¬ 
tically. The toothless Sturgeon draws in its prey by pow¬ 
erful suction. The Hag-fish has a single tooth, which it 
plunges into the sides of its victim, and, thus securing a 
firm hold, bores its way into the flesh by means of its saw¬ 
like tongue. But Fishes are usually well provided with 
teeth, which, being sharp and curving inward, are strictly 
prehensile. The fins and tongue are not prehensile. A 
mouth with horny jaws, as in the Turtles, or bristling with 
teeth, as in the Crocodile, is the only means possessed by 
nearly all Amphibians and Reptiles for securing food. 
The Toad, Frog, and Chameleon capture insects by dart ¬ 
ing out the tongue, which is tipped with glutinous saliva. 
The constricting serpents (Boas) crush their prey in their 
coils before swallowing; and the venomous Snakes have 
a poison-fang. No reptile has prehensile lips. All Birds 
use their toothless beaks in procuring food, but birds of 
prey also seize with their talons, and Woodpeckers, Hum¬ 
mers, and Parrots with their tongues. The beak varies 
greatly in shape, being a hook in the Eagle, a probe in the 
Woodpecker, and a shovel in the Duck. 
Among the Quadrupeds we find a few special contriv¬ 
ances, as the trunk of the Elephant, and the long tongues 
of the Giraffe and Ant-eater; but, as a rule, the teeth are 
the chief organs of prehension, always aided more or less 
by the lips. Ruminants, like the Ox, having hoofs on 
their feet, and no upper front teeth, employ the lips and 
tongue. Such as can stand erect on the hind-legs, as the 
Squirrel, Bear, and Kangaroo, use the front limbs for hold¬ 
ing the food and bringing it to the mouth, but never one 
limb alone. The clawed animals, like the Cat and Lion, 
