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, 



