94 
ON" THE PHYSIOGIirOMY OF SERPENTS^ 
ing of the skin during the hybernation. It would be very 
interesting to know how many moults serpents undergo in 
warm climates, where the state of sleep does not take place. 
A state of domesticity, a mode of life little natural to these 
animals, remarkably influences the functions of the skin, the 
epidermis of which does not renew itself in fixed and de- 
terminate periods ; frequently this operation is very long, 
and so painful that the animal suffers much, or it is some 
times followed by death. In order to reject the old epi- 
dermis, which begins to detach itself at the head, and espe- 
cially along the borders of the lips, the serpent passes it- 
self through mosses, grasses, or heaths, and contrives, by 
means of slow and continued movements or frictions, to 
disengage gradually the exterior layer of the skin, which 
is already replaced below by a new epidermis. The spoils 
thus removed are found inverted from one end to the other, 
forming a sac with a reticulated surface more or less diapha- 
nous, more wide than the body of the snake, because of the 
dilatation of the membranous intervals, and presenting, 
with the exception of those of the mouth and the nostrils, 
no other orifice than the anus ; for it is well known that 
the hemispherical membrane which protects exteriorly the 
globe of the eye, is part of the integuments, and comes off 
along with the rejected skin. This skin, at first soft, soon 
dries, and is easily preserved in cabinets ; but it is rare to 
find it entire, because it is often torn in the operation we 
have described. We possess some specimens of several 
foreign species, which prove that the moulting is produced 
in the same manner in all serpents. 
The changes which Ophidians undergo, before they iiave 
acquired their full growth, have been as yet little studied. 
Thus, sometimes, as we have stated above, the livery of 
the two sexes presents considerable varieties at different 
periods of life. The males have often a more thick and 
longer tail than the females, probably because they have the 
organs of generation lodged in a cavity at the base of that 
member ; the females, on the other hand, acquire a size 
greater than that of the male, and their trunk is then of a 
more considerable volume. We are entirely ignorant of 
the age to which the different races of snakes arrive, 
