The most common and well-known of the rat tlesnakes is that one (Crotalus durisRus) former ly abundant all over the East, from the White Mountains in New Hampshire, and Lake Superior in the North, to the borders of the dry plains.
It is larger in the Southern States than north ward, and oecasionlly reaches a length of five feet, with a diameter in that case of four to five inches. The ground-color above varies from bright tawny to dark brown. A light line runs from the mouth to the eye, with a dark patch be low; and the body is marked with three rows of confluent irregular brown spots, forming about 21 zigzag crossbars. The head is oval in outline. This snake inhabits wooded regions, avoiding prairies. It is especially fond of rocky districts, and hence is most 'numerous among mountains, where it is inclined to gather in considerable numbers in certain holes and caverns in the autumn, in order to undergo the winter sleep in closely entwined companies. About nine young are born annually in mid-summer. The Southern States have a still larger species known as the `diamond rattlesnake' (Crotalus adamanteus) on account of the rhomboidal black blotches, each perfect in all its angles, and edged with yellow, which ornament its yellowish body. This snake sometimes reaches, on the Mangrove Islands of western Florida, a length of eight feet, and has so great a thickness that large individuals may be regarded as the most bulky of all veno mous snakes, for the Oriental cobras, although sometimes longer, are far more slender. The range of the diamond rattlesnake extends along the coast from North Carolina to Texas, and a variety ranges westward to Lower California. Two other similar and almost equally large and dreadful snakes are Crotalus molossus and be siliscus. Southern California also has a remark able species (Crotalus rubcr), which has an ob long head, and whose markings are deep red or sometimes chestnut, upon a paler reddish ground.
The rattlesnake of the plains (Crotalus eonflu entus) is a light-colored, obscurely marked, rath er small species. It is highly variable in form and color. and is the kind constantly found in prairie-dog towns. Several other species occur in the Rocky Mountain region and Northern Mex ico, one of which (Crotalus eerastes) is the char acteristic snake of the deserts of the valleys of the Rio Colorado and Gila, where the people call it 'sidewinder,' from its habit of progressing side wise instead of in the usual way. It takes its specific name from the fact that the plates above the eyes are thickened into hornlike cones, some times of considerable height. It is not of large size, hut is dangerous because of the virulence of its poison.
The small, active prairie rattlesnakes, now greatly reduced in number, differ sufficiently from the genus Crotalus to be set apart into the genus Sistrurus. One of them (Sistrurus mil iarius) is the ground-rattler of the Southern States, too frequently met with in stubble fields and grassy places. A Northern congener is the black rattlesnake or `massasauga,' once common between the Alleghany Mountains and the plains, but now nearly exterminated except on the fron tier. This species (Sistreres catenates) may reach a length of 30 inches, and is brown, with a series of darker brown transverse spots on the back, beneath each of which is a small brown spot forming a linear series along the sides, lts rattle is small, but can be heard at a considerable dis tance, and its bite is likely to be exceedingly troublesome to men and domestic animals, al though not often fatal. These snakes prefer low, wet ground, the draining of which by the spread