ORDER OPHIDIA. 293 



of cochlea, and three semi-circular canals ; but none of them 

 present any external aperture, nor pavilion for the ear. The 

 box of the tympanum itself seems to be wanting, as well as 

 the membrane which closes it. The only osselet which is 

 there observed touches, by its exterior extremity, the bone 

 which supports the lower jaw, is surrounded by the flesh, 

 and is applied to the fenestra by a small concave plate whose 

 edges are irregular. 



The apparatus, therefore, destined to the perception of 

 sounds is far from being perfect in these animals, and accord- 

 ingly they do not appear to have the sense of hearing very fine. 



It is the same with the sense of smelling, the organs of 

 which, in the ophidians, appear to be still more incomplete. 



Their nostrils are short, very little developed, usually 

 simple, and situated at the extremity or on the sides of the 

 muzzle. In some species, as the ammodytes, and coluber 

 nasica, they are prolonged so as to represent a kind of nose. 

 Their nasal fosses exhibit nothing which can be compared to 

 the sinuses which are hollowed in the bones of the head in 

 mammalia and birds. The projecting laminae which divide 

 the interior of these cavities, have not been described in a 

 satisfactory manner. The pituitory membrane is furnished 

 with a net-work of blackish vessels. 



The crotali, and some other venomous serpents, have un- 

 derneath, and behind each nostril, a hole tolerably deep, but 

 the use of which is vmknown. 



The sense of taste in these animals whose general ' history 

 we are thus sketching, is very feeble, and perhaps still less 

 developed than that of olfaction. 



The tongue of the ophidians is, in fact, very extensible, 

 and is terminated by two long points, which though ex- 

 tremely mobile, are semi-cartilaginous and corneous. Its 

 surface is smooth, though soft and humid. This organ 

 appears rather destined to seize the aliments than to perceive 



