110 COMPARATIVE DENTAL ANATOMY 



as the Cobra, they are also reproduced indefinitely 

 as lost. 



The non-poisonous snakes have two rows of 

 teeth in the upper series and one in the lower, 

 which are strongly recurved and irregular in size. 

 They are ankylosed to the jaw, and reappear as 

 lost. They are composed of hard dentin with a 

 thin external layer of cementum and enamel. In 

 the Boa Constrictors, the teeth are slender, coni- 



FlG. 36. — Teeth of Python regius. 



cal, and slightly recurved. This enables them to 

 creep up with the alternating motions of the jaws 

 over disproportionately large objects, and force 

 them backward into the oesophagus. The teeth of 

 the Pythons (Fig. 36) are all simple recurved 

 cones. Some are grooved and perhaps con- 

 stricted at the neck. In the Colubers the teeth 

 are similar, — the largest being in front and dimin- 

 ishing in size backward. 



