66 
OK THE PHYSIOOKOMY OF SEEPEKTS. 
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 pair is to be traced sending 
off its branches, as in man, to the eye and to the upper 
and to the lower jaws. The great sympathetic nerve in- 
terlaces, ifi so many points, with the par vagum, that it is 
impossible to trace its origin with accuracy. 
With respect to intellectual faculties. Ophidians are 
evidently in the same list as the animals of the two first 
orders of the class of Reptiles. The power 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 when such a member as the tail is cut off, it 
is never reproduced. 
OF THE SEKSE 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 serpents, 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, PI. 5. fig. 126 and 127 ' 
132 and 133 is the figure of the brain of Naja Haje, of the Aspic, and of 
the Viper with parallel rays. 
