66 ON THE rilYSlOGNOMY OF SERrENTS. 



very long peduncle ; we observe on their posterior sur- 

 face the optic lobes, of considerable size, and passing below 

 the hemispheres to reach the eye, and to form the optic 

 nerve. The cerebellum is a small organ situated behind 

 the optic lobules, almost in a line with the spinal marrow, 

 and shews but a small protuberance.* The extreme deli- 

 cacy of the nerves of the head renders the examination of 

 those parts very difficult. Besides the olfactory, optic, 

 and auditory nerves, the fifth i)air is to be traced sending 

 off its branches, as in man, to the eye and to the upper 

 and to the lower jaws. The gi*eat sympathetic nerve in- 

 terlaces, in so many points, ^vith the par vagum, that it is 

 impossible to trace its origin with accuracy. 



Witli respect to intellectual faculties, Ophidians are 

 e\ndcntly in the same list as the animals of the two first 

 orders of the class of Reptiles. Thepowcr of regeneration 

 of the organs, which exists in Ophidians, has often been 

 exaggerated ; but it is little probable that it should be 

 greater than in the Saurians, or in the Chelonians. This is 

 certain, that a\ hen such a member as the tail is cut off, it 

 is never reproduced. 



OF THE SENSE OF SMELL. 



Serpents have not a very delicate sense of smell. The 

 extent of the mucous membrane of the nose is not consider- 

 able, on account of the simple form of the turbinated bones. 

 The cavity of the nose differs in extent in the different 

 species. The nostrils vary much from genus to genus, 

 both in position, shape, and size. It may be received as 

 an established rule, that purely aquatic species have small 

 nostrils, directed upwards, and most frequently capable of 

 being shut by a valve, while the nostrils of the terrestrial 

 species, or of those that inhabit trees, are generally lateral 

 and very open. In the burrowing sei'pents, those orifices 

 almost always have an orbicular form, and are very small ; 

 they have the same form, but are more open than the nos- 



* See Serres, Anat. Comp. du Cerveau, Atlas, PL 5. fig. 126 and 127 ' 

 132 and 133 is the figure of the brain of Naja Haje, of the Aspic, and of 

 the Viper ^Yith parallel rays. 



