SNAKES. 
240 
as a lateral remnant of the hinder frontal. The space between the two last-named 
shields is occupied by a series of small shields, of which the front ones are the 
largest: and between the supraocular shields commence the long keeled scales 
covering the body, where they are arranged in from twenty-five to twenty-seven 
longitudinal rows. The ground-colour of the upper surface is a dull greyish brown, 
upon which are two rows of large, irregular spots, which may unite into zigzag 
crossbands, and are gradually lost on the dark tail; the under-parts being yellowish 
white, marked with small black dots. Generally about 4^ feet in length, this 
species may grow to 6 feet. 
Diamond In the Southern United States the commonest member of the 
Rattle-Snake, genus is the diamond rattle-snake ( C. adamanteus), represented in 
the upper figure of the accompanying illustration, which is not only the most 
beautiful, but likewise the largest species, adult females (which in this group are 
always larger than the males), not unfrequently measuring 6 feet in length. 
... From the common rattle-snake it may be distinguished by the large and narrow 
head, on which the shields are but slightly developed, the presence of three pairs of 
shields between the rostral and supraocular on the top of the muzzle, by the scales 
of the body being always arranged in twenty-seven rows, and also by the coloration. 
The small rostral shield is markedly triangular, the slightly developed frontal has 
a roundish pentagonal form, and the great supraocular shield a distinctly over¬ 
hanging edge. After shedding, the new skin is of a beautiful greenish, or 
occasionally golden-brown, ground-colour; upon this is a triple lozenge-shaped 
chain-pattern on each side of the back, the golden yellow lines of which stand out 
in marked contrast to the dark diamonds of the ground-colour. A blackish brown 
band runs from the muzzle through each eye to the corner of the mouth ; and the 
top of the head is either uniformly coloured, or ornamented with irregular markings, 
south American Of the six species of the genus, four are confined to North 
Rattle-Snakes. America, and only one is found to the southward of the Isthmus of 
Panama. The latter species ( C . horridus), which is represented in the lower figure 
of our illustration, approaches the common species as regards the arrangement of 
the shields on the head, while in coloration it is like the diamond rattle-snake. 
From the former it may be distinguished by the circumstance that the two pairs of 
shields between the rostral and the supraocular have no small shields between 
them, so that they come in contact with one another in the middle line; while from 
the latter the larger size of the lozenges on the body, and the presence in each of 
a light-coloured centre will serve as a sufficient distinction, in addition to the 
different arrangement of the head-shields. 
In noticing the habits of these snakes our remarks will chiefly 
xi H. DILS. 
relate to the North American species. As we have already said, 
rattle-snakes chiefly frequent dry and sandy localities, more especially when they 
are covered with bushes; but we have to add that in North America they fre¬ 
quently take up their abode in the burrows of the prairie-marmot. Formerly it 
was thought that the snakes and marmots lived together in harmony, but it is now 
ascertained that the former prey on the young of the latter. The general food of 
rattle-snakes consists of small mammals, birds, lizards, and frogs, the latter being 
especial favourites; but mammals as large as a mink have occasionally been taken 
