72 Dr. Russell and Mr. Home’s Observations on the 
lateral orifices in serpents, and the bags to which they lead, have 
no communication with the organ of hearing. Another fact 
ascertained by him is, that serpents distinguished by lateral 
orifices, have a cavity situated between the bag and the eye, 
which, so far as I know, has not been observed before. 
Mr. Home’s Description , and Remarks. 
The orifices situated between the eye and the nostril, in the 
rattle-snake, and in some species of coluber, do not lead to the 
nostril or to the ear, but to a distinct bag, of a rounded form ; 
there is a hollow of the same shape surrounded by bone, and 
adapted to receive it. Dr. Tyson’s description of the rattle- 
snake is tolerably accurate : he says, “ between the nostrils and 
“ the eyes, but somewhat lower, were two orifices, which I took 
“ for the ears ; but after, I found they only led into a bone, that 
“ had a pretty large cavity, but no perforation.” * 
The cavity which Dr. Tyson describes to be in the bone, is a 
cup, formed by the bones of the skull and those of the upper 
jaw ; it is in shape not unlike the orbit, and is formed in a similar 
manner. 
These bags bear a relative proportion to the size of the snake ; 
they are lined, as also the eyelids, with a cuticle, which forms 
the transparent cornea, making a part of the outer cuticle, and 
is shed with it ; and, when examined after the snake has cast it 
off, their shape is more perfectly seen than under any other 
circumstances. 
In the annexed figures, one of these bags is represented in 
different views ; all of them of the natural size, both in the 
Fer-de-lance or yellow snake of Martinico, and in the detached 
* Phil. Trans. Vol. XIII. p. 26. 
