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IX. Observations intended to show that the progressive Motion of 
Snakes is partly performed by means of the Ribs. By Everard 
Home, Esq. F. R. S . 
Read February 27, 1812. 
O n a former occasion I laid before the Society a description 
of the mechanism of the hood of the cobra de capello snake 
of the East Indies, the coluber naja of Linnaeus, in which the 
ribs of the neck are shewn to be formed in a particular man- 
ner ; so that when they are raised, the skin becomes stretched 
out, and puts on the appearance of a hood. 
The ribs so employed have several peculiarities, which, I 
took for granted, were confined to those of the neck, for I was 
not in possession of the bodies of the snakes, and therefore 
could not examine the others ; but have since found that many 
of these peculiarities are not only common to all the ribs of 
this snake, but to those of the whole tribe. 
This fact, as it escaped my observation at that time, would 
have still done so, had it not been for the following circum- 
stances. 
A coluber of unusual size, lately brought to London to be 
exhibited, was shewn to Sir Joseph Banks ; the animal was 
lively, and moved along the carpet briskly: while it was doing 
so, Sir Joseph thought he saw the ribs come forward in suc- 
cession like the feet of a caterpillar. This remark he imme- 
diately communicated to me, and gave me an opportunity of 
.seeing the snake and making my own observations. 
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