OF THE BONES OF THE HEAD. 
33 
vestiges of these bones ; they disappear in the Tortrix and 
the Elaps, while they are highly developed in the Boa, 
in many Vipers, &c. ; but in the Acrochordus they extend 
to the anterior frontals, and thus replace the supraorbitars, 
another pair of supernumerary osseous pieces, peculiar to 
the Pythons, and wedged between the frontals. 
All the other bones of the head belong more or less di- 
rectly to the great apparatus destined for mastication, if 
such a term may be employed in describing the animals of 
which we now treat. This apparatus is naturally divided 
into two parts : the first consists of the upper jaw and its 
appendages ; the second is formed by the lower jaw, and 
the pieces which suspend it from the cranium. It is first 
necessary to describe the intermaxillary^ a little bone placed 
transversely at the end of the snout, rarely armed with 
teeth, the handle of which is lodged between the nasals and 
the vomer ; being in other points free, it follows the move- 
ments of these bones. The maxillaries^ equally free at 
their anterior extremity, are united to the cranium, through 
the medium of the anterior frontals ; their posterior extre- 
mity is bound to the external pterygoids ; but it by no 
means follows that their form and their mode of attach- 
ment should always be the same in the different genera of 
Ophidians. In non- venomous serpents, this bone is pretty 
long, horizontally placed, armed with a row of numerous 
teeth, and always united by a bridge more or less wide to 
the palatal bones, or even to the internal pterygoids. In 
the poisonous snakes, on the contrary, it is reduced to a 
very short piece, and always smaller according as the 
serpent is more poisonous. We observe in the venom- 
ous snakes, that this bone only supports the fangs, is arti- 
culated only to the anterior frontals, and is free in all the 
rest of its extent. It is evident, that the development of 
the external pterygoids, real levers of the upper jaw, should 
be in the inverse ratio to that of the maxillaries. This 
piece, intermediate between the maxillaries and the internal 
pterygoids, is always without teeth, and becomes more 
slender as it increases in length ; it consequently shews 
itself in the shape of a linear and very slender stylet in 
venomous snakes. The internal pterygoids, which unite 
