OF REPTILES. 
31 7 
known, that as serpents generally abandon their eggs, 
their young are perfect in all their parts, and capable of 
providing for their own subsistence immediately on 
being hatched. 
On the whole, as these two animals agree in so many 
conspicuous, important and peculiar characters, and as 
no material difference between them has yet been clearly 
pointed out, excepting that of size; the Society will 
probably feel justified in considering them individuals 
of the same species, and entitled to the same name, until a 
more close examination of the great Serpent shall have 
disclosed some difference of structure, important enough 
to constitute a specific distinction. 
JOHN DAVIS, 
JACOB BIGELOW, 
Boston , 1 1th Oct . 1817. FRANCIS C. GRAY, 
Ratte Snake. (PL 52.) The colour of the rattle- 
snake, which is bred both in # North and South America, 
but in no part of the old world; is yellowish brown above, 
marked with broad transverse bars of black. Both the 
jaws are furnished with small sharp teeth, and the upper 
one has four large curvated and pointed fangs. At the 
base of each is a round orifice, opening in a hollow that 
appears again near the end of the tooth in the form of a 
small channel; these teeth may be raised or compressed. 
When the animals are in the act of biting, they force 
out of a gland near the roots of the teeth, the fatal juice. 
This is received into the round orifice of the teeth, con- 
veyed through the tube into the channel, and from 
thence with unerring direction into the wound. The tail 
is furnished with a rattle, consisting of joints loosely con- 
nected; the number of these is uncertain, depending in 
some measure on the age of the animal, being supposed 
to increase annually by an additional joint. The young 
snakes or those of a year or two old, have no rattle 
at all. 
As the tail of those snakes, which are the most dreaded 
of all serpents, keep rattling upon the slighest motion, 
passengers are thus providentially warned of their ap- 
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