44 ON THE PHYSIOGNOMY OF SERPENTS. 



during the existence of the animal.* Every tooth, before 

 its appearance, is covered by a membrane, which contains 

 also nutritive matter. In ossifying, the tooth fixes its base 

 in the hollow representing the alveoli, and roots itself, as 

 the ossification advances, very often, especially in the fangs ; 

 a small orifice at their base remains behind, for the entrance 

 of the vessels and the nerves : thus the fangs are more in- 

 thnately connected with the bones than the other teeth. 

 We often perceive the genns of new teeth concealed in the 

 germs near the older teeth, and intended to replace the 

 latter when they are accidentally destroyed ; soon the new 

 tooth moves to occupy the empty alveolus, where it fixes 

 itself by the development described.t The fangs being 

 nu)re exposed than the other teeth, nature has watched 

 over their reproduction, in placing behind them several 

 genns of new fangs, of which the number is sometimes as 

 high as six, and they succeed in every degree of develop- 

 ment ; it is not known whether the old fangs are shed 

 spontaneously at certain epochs, and whether this replacing 

 of the fangs is a gradual process. The internal structure 

 of these organs is remarkable, in having the conduit for 

 the poison separated by a partition from the hollow^ con- 

 taining the nutrient apparatus of the tooth .J 



The solid teeth are found equally in all Ophidians ; but 

 their number, their form, and their arrangement, present 

 considerable differences in their various species. With 

 the exception of the Oligodon, which is without palatal teeth, 

 we always reckon four rows of teeth in the upper, and two 

 in the lower jaw. Intermaxillary teeth are only found in 

 the Pythons, and occasionally in the Tortrix scytale : their 

 number is rarely more than four. The solid teeth of 

 Ophidians are most usually all of equal length ; but in the 

 Boa they augment in size towards the end of the muzzle ; 

 and the reverse occurs in some species of Coluber, Tropi- 

 donotus, &c. ; the Lycodons exhibit, at the anterior 



* See Fig. 1, 2, 3, and 4, PI. 16, of my Memoir already quoted. 



t See the Memoir on the Reproduction of the Fangs, published by 

 Rosa, a memoir which I only know by the extract given by Meckel. 

 Trad. Allem. de VAnat. Comp. de Cuvier, t. iii. p. 126, 



\ See the figures of the fangs in the work of Fontaxa. 



