44 
Q-E THE PHTSIOa:N^OMT OF SEEPENTS. 
during the existence of the animal.^ Every tooth, before 
its appearance j 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- 
timately connected with the bones than the other teeth. 
We often perceive the germs 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 
more exposed than the other teeth, nature has watched 
over their reproduction, in placing behind them several 
germs 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 iri 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, S, and 4, PL 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 Fontana. 
