the neck very thin; its body increases in diameter toward the middle and gradually tapers oil to the tail. In the cobra the head, neck, and body are of the same thickness until the tail commences. In the rattlesnake the eyes have a vertical pupil, like a cat's; in the cobra the pupil is round. In the rattlesnake the fangs are long, well curved, very movable, thin, and with the end of the poison duct coming out almost in the same line with the point of the fang; in the cobra the fang is very short, slightly curved, scarcely movable, strong, and with the end of the poison duct coming out at a large angle with the point. In disposition the rattler is much more sluggish and not nearly so timorous as the cobra. To meet an assailant, the rattlesnake will arrange himself coiled carefully, like a spring, in a horizontal position; while the cobra prepares no coil, but raises himself up on high perpendicular from the ground. As to the manner of securing their prey, the rattlesnake is like a cat: he lies in wait for it in a suitable locality, and then springs on it unawares, generally waiting till its death struggles have ceased before swallowing it. The cobra, on the contrary, hunts up his victims, pursues them like a dog, and swallows them alive when caught. There is also, as Dr. Weir Mitchell has shown, a marked chemical variance between their poisons.
All these differences are, as a rule, applicable to their respective classes; and it is worthy of mention that in the several points enumerated, excepting as regards the poison arrangements, the Viperidæ agree with the true boas and the Elapidæ with the colubrine or common harmless snakes. So it will be understood that the cobra is rather a cousin to the black snake than to the rattler. In searching for his prey, he glides about without anything remarkable in his appearance to denote that he is a cobra; but, when excited by fear or anger, he raises his head and from one third to one half of his body perpendicularly from the ground, while the remainder is gathered beneath into a coil of support. At the same time the upper ribs, from the head downward for five or six inches or more, spread themselves out laterally, carrying the skin with them, thus making of his neck part a thin, flattened oval disk four or five inches broad. This wide flatness of the neck is called, the "hood," and above it the head appears pointing horizontally to the front. His disposition is so extremely nervous and timid that he will strike at a moving adversary long before he comes near enough to reach him with effect. If you stand before a cobra thus erect and alarmed, and move alternately your left and right hands up and down, he will strike repeatedly to the left and right, following your motions, bringing his head and neck flat on the ground each time, and at every stroke drawing closer to you. In striking thus he hisses audibly
