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HOW DO WE CLASSIFY ANIMALS? 



Snakes. Probably the most disliked and feared of all common 

 animals are snakes. This feeling, however, is rarely deserved, 

 for, on the whole, our common snakes are beneficial to man, 

 for they live largely on injurious animals, such as rodents, insects, 

 and slugs. 



Locomotion. Snakes are almost the only vertebrates without 

 appendages. Although the limbs are absent, the pelvic and 

 pectoral girdles are developed. The very long backbone is made 

 up of a large number of vertebrae. As many as four hundred are 



Wright Pierce 



The rattlesnake is one of the few poisonous snakes. The snake is coiled, with 

 rattlers buzzing, ready to strike. 



found in the boa constrictor. Ribs are attached to all the vertebrae 

 in the region of the body cavity. They progress with a gliding 

 motion caused by pulling and pushing the body along the ground, 

 a leverage being obtained by means of the broad, flat scales, or 

 scutes, on the under side of the body. 



Feeding habits. The mouth is a wide, slitlike opening extending 

 nearly around the anterior end of the head, and is therefore capable 

 of wide distention. A snake holds its prey by means of incurved 

 teeth. In the poisonous snakes two of these teeth are hollow or 

 grooved, and serve as a duct for the passage of poison. The 

 poison glands are at the base of the curved fangs in the upper jaw. 



