Colour yellowish-brown, beautifully marked with 6 or 7 longitudinal series of alternating, elongate, dark brown, black- and white-edged spots, separated by narrow interspaces of the ground-colour; a pair of diverging dark bands on the top of the head, separated by a narrow pinkish-white streak; belly pinkish or yellowish, spotted with dark brown. Total length, 600 millimetres; tail 60. _Habitat_: Tableland of Mexico. (10) C. LEPIDUS.--12 supralabials; scales in 21 or 23 rows, dorsals strongly keeled; 153-169 ventrals; 24-31 subcaudals. Colour brown or greenish-grey, with dark brown or jet-black light-edged cross-bands, narrowing on the sides; two dark spots, or a =V-= or heart-shaped black marking on the nape; belly dirty white, spotted with brown. Total length, 350 millimetres; tail 60. _Habitat_: Western Texas, New Mexico, Arizona, North Mexico. (11) _C. cerastes_ (Horned Rattle-Snake; fig. 76).--Supraocular transformed into a raised horn-like process; 11-13 supralabials; scales in 21 or 23 rows; dorsals feebly keeled, each scale along the middle of the back with a central tubercular swelling; 146 ventrals; 17 subcaudals. [Illustration: FIG. 76.--_Crotalus cerastes_ (Horned Rattle-Snake.) (After Baird and Stejneger.)] Colour yellowish, with a dorsal series of rather indistinct brown blotches; a narrow brown streak from the eye to the angle of the mouth. Total length, 250 millimetres; tail 20. _Habitat_: Desert regions of Southern California, Nevada, Arizona, and Utah. _F.--HYDROPHIINÆ (SEA-SNAKES)._ The Sea-Snakes, which are found in great numbers on the shores of the Indian Ocean, are common throughout the whole of the tropical zone of the China Sea and the Pacific. They are met with from the Persian Gulf to the west coast of Equatorial America, but are entirely absent from the east coast of the same continent and the west and east coasts of Africa. They often travel in companies. All are poisonous, and very savage. They never come to land, and move with difficulty if taken out of the water, although they are excellent swimmers. It is impossible to keep them in captivity in aquariums, and they die in two or three days. Their food consists of fishes and crustacea. Their tail is prehensile, and they make use of it as an anchor to attach themselves to coral reefs when they wish to rest. They generally float on the surface of the waves, but can dive to great depths, thanks to the extreme dilatability of their lungs, which enables them to store up large reserves of air. They are viviparous. In these snakes, the head, which is always very small, is scarcely distinct from the body. It is often covered with nine large shields. The body is laterally compressed, and the tail, which serves as a fin, is similarly flattened. The nostrils open on the upper surface of the snout, between the nasal shields. The eyes are always very small.