so 
APPENDIX No. II. 
I have, in the course of the last three years, received two Colubers from Java ; and, by favour of Dr. 
Clark, two from Martinico ; all four venomous, and distinguished by lateral orifices. In the month of 
January, 1803, Dr. Garthshore presented me with a specimen of the yellow snake of Martinico in excel- 
lent preservation. 
Six subjects, distinguished by these lateral orifices now in my possession, offering a fair opportunity to de- 
termine a curious circumstance in comparative anatomy, the specimens were submitted to my friend Mr. 
Home, of whose assistance I had more than once availed myself in similar investigations. My request was 
once more attended to; and the subjoined Description and Remarks were received in return. 
Among the specimens submitted to Mr. Home, was one of the Bodroo Pam , in the description of which, 
lately published,* I have misrepresented the orifices now in question as the nostrils, having intirely over- 
looked the real nostrils. 
W hile the anatomical disquisitions were going on, inspection was made into some of the numerous collec- 
tions of serpents preserved in the Museums in London. In the British Museum I was shewn, exclusive of the 
Rattle-snake and the Fer-de-lance, four or five Colubers, t with lateral orifices; in the Leverian Museum I 
found two or three; in the Hunterian Museum, two Colubers,? and three Boae ;§ and in that of Mr. Heaviside, 
one Coluber.jl 
The total found in the Museums above-mentioned, (exclusive of the Rattle-snake,) were ten or eleven 
Colubers, and three Boae; which, added to five Colubers in my own possession, amount to eighteen or nine- 
teen subjects furnished with lateral orifices. 
It appears on the whole, that the lateral orifices have hitherto been found only in venomous serpents. 
That (exclusive of the Rattle-snake), they have been found in fifteen or sixteen species of Colubers, and in 
three of the Genus Boa. 
That they have not as yet been discovered in any of the Genus Anguis. 
Mr. Home’s investigations have clearly established that these 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 cuticle of the Rattle-snake. The 
appearance in the Bodroo Pam is exactly the same ; but, as the bag in that snake is of a smaller size, it was 
considered unnecessary to give a representation of it. 
In the deer and antelope there are bags, in the same relative situation repecting the eye and the nose, 
* Account of Indian Serpents collected on the Coast of Coromandel, No. IX. 
t No. 977, 1058. §.No. 893, 1016, 1046. || No. 64. 
f All I believe Nondescripts. 
Philos. Trans, vol. xiii. p. 26. 
