Venoms: Venomous Animals and Antivenomous Serum-therapeutics. A. Calmette
streaks behind the eyes. The belly is whitish, dotted with black.
Total length, 890 millimetres; tail 110.
(c) Cerastes.
The vipers belonging to this genus are much more common in North Africa, and we shall therefore study them in conjunction with the African snakes. Cerastes cornutus alone, the special habitat of which is Egypt, is sometimes met with in Arabia and on the eastern bank of the Suez Canal.
(d) Echis.
Echis carinatus (the Phoorsa). (Fig. 30).—This viper is characterised by the subcaudal shields being arranged in a single row. It is savage and very aggressive, being always ready to attack. Its length does not exceed 600 millimetres at the most. The colour of the body is grey, more or less dark and adorned with streaks, spots, and dots of blackish-brown. The back displays yellowish-white wavy lines, forming X-shaped markings. The upper side of the head exhibits a yellow spot surrounded by brown, and other small black spots, the whole arrangement forming a fairly good representation of a cross.
Fig. 30.—Echis carinatus. India. (After Sir Joseph Fayrer.)
This species is found in India, Persia, Baluchistan, Arabia, and Palestine; while, as we shall see, it also occurs in Africa. It is fairly common in the environs of Aden.
In moving over the ground a peculiar sound is produced by the friction of its scales. It is capable of springing with great agility a fairly long distance on to its prey. When it believes itself in danger it coils up, doubling its body twice in the shape of a crescent, in the middle of which it places its head, ready to strike. Its venom is very rapid in taking effect.
2.—CROTALINÆ.
(e) Ancistrodon.
The snakes belonging to this genus of Crotalinæ are found in Central and Eastern Asia, but three important species occur in the New World, in the United States and Central America. The head is covered with nine large symmetrical shields, but the internasals and præfrontals are sometimes broken up into scales. The body is cylindrical; the tail rather short; the subcaudal scales are arranged in one or two rows.
A. acutus.—The snout of this snake is prolonged into an appendage directed forwards. The head-shields are finely granulate. Body scales arranged in 21 rows; 162–166 ventrals; 58–60 subcaudals.
Coloration brown on the back, with blackish-brown X-shaped spots; head dark brown, yellow on the cheeks, with a black band running from the eye to the angle of the jaw; belly yellowish, spotted with brown, with a series of large black transverse blotches.
Total length, 1,500 millimetres; tail 200.
Habitat: Upper Yang-tse, China.
A. halys.—Snout prolonged into an upturned appendage, blunt at the tip; 7–8 supralabial scales, the third of which forms part of the margin of the eye; body scales in 23 rows; 149–174 ventrals; 31–44 subcaudals.
Coloration yellowish, grey, red, or pale brown above, with darker spots or cross-bars. A black spot on the snout; two black spots on the vertex; a dark, light-edged band on the temple; belly whitish, more or less speckled with grey or brown.
Total length, 490 millimetres; tail 65.
Habitat: From the borders of the Caspian Sea and the Ural River to the Upper Yenisei; Turkestan.
A. intermedius.—Resembles the foregoing very closely, but the snout is not turned up at the end.
Total length, 750 millimetres; tail 85.
Habitat: Central Asia, Eastern Siberia, Mongolia, and Japan.
A. blomhoffii.—Similar to A. halys, but the snout is not turned up at the end, and the body scales are in 21 rows; 137–166 ventral scales; 29–55 subcaudals.
Coloration very variable; grey, brown, or red above, with large black-edged spots arranged in pairs; black, light-edged band on the temple; upper lip uniformly yellow or red; belly yellow or reddish, more or less spotted with black, or almost entirely black.
Total length, 720 millimetres; tail 100.
Habitat: Eastern Siberia, Mongolia, China, Japan, Siam.
A. himalayanus.—Snout scarcely turned up, with a hard tip; 5–7 supralabial shields. Body scales in 21 (rarely 23) rows; 144–166 ventrals; subcaudals in 35–51 pairs.
Fig. 31.—Ancistrodon hypnale.
(The Carawalla of Ceylon.) (After Sir Joseph Fayrer.)
Coloration brown, with black spots or transverse bands; black, light-edged band from the eye to the angle of the mouth; belly dark brown, or more or less whitish.
Total length, 590 millimetres; tail 90.
Habitat: Himalayas (5,000 to 10,000 feet), especially in the North-west; Khasi Hills.
This snake feeds chiefly on mice.
A. rhodostoma.—Snout pointed, somewhat turned up at the tip: 7–9 supralabial shields; body scales in 21 rows; 138–157 ventrals; 34–54 subcaudal pairs.
Coloration reddish, grey, or pale brown above, with large angular, dark brown, black-edged spots arranged in pairs or alternating. Vertebral line almost black; lips yellow, speckled with brown; brown, black-edged band, running from the eye to the angle of the mouth. Belly yellowish, spotted with greyish-brown.
Total length, 810 millimetres; tail 90.
Habitat: Java.
A. hypnale (fig. 31).—Snout more or less turned up, with a hard, pointed end; 7–8 supralabial shields; body scales in 17 rows; 125–155 ventrals; 28–45 subcaudal pairs.
Coloration very variable; brown, yellowish, or greyish above, sometimes with dark brown spots or transverse bands. Cheeks brown, with a longitudinal, white, black-edged streak on each side of the neck. Belly more or less speckled with dark brown.
Total length, 480 millimetres; tail 65.
Habitat: Ceylon, and Western Ghats of India as far north as Bombay.
In Ceylon this snake is known as the Carawalla. It is much dreaded, but its bite is not rapidly fatal.
(f) Lachesis.
This genus has many representatives in Asia and the New World. The American species are for the most part of larger size and more formidable.
They are characterised by a triangular head, covered with small scales or small shields, and by a cylindrical or compressed body. The Asiatic species have the subcaudal scales in two rows and the tail short, and often prehensile, which enables them to climb trees or bushes, where they lie in wait for their prey.
Their classification is based upon the following characters:—
A. First infralabial scale in contact with its fellow.
I. Scales in 21–25 (rarely 27) rows; 129–158 ventrals; 21–57 subcaudals; 5–9 series of scales between the supraocular shields; tail non-prehensile.
Fig. 32.—Lachesis okinavensis. (After G. A. Boulenger, op. cit.)
(1) L. monticola.—Supraocular shields large, separated by 5–8 scales; snout obtuse.