Venoms: Venomous Animals and Antivenomous Serum-therapeutics. A. Calmette
followed by other teeth; a long tooth at the end of each ramus of the mandible. Head narrow, elongate; eye moderate, with round pupil; nostril between two shields. Body slightly compressed; scales smooth, narrow, very oblique, in 13–23 rows; ventrals rounded. Tail long; subcaudals in 2 rows.
(1) D. viridis.—211–225 ventral scales; 107–119 subcaudals.
Colour uniform olive-green. Shields on the head edged with black; lips yellow; belly and tail yellow, with scales and shields bordered with black.
Total length, 1,830 millimetres; tail 460.
Habitat: West Africa, from the Senegal to the Niger; St. Thome Island.
(2) D. jamesonii.—Coloration as before. Scales in 15–19 rows (19–21 on the neck); 210–235 ventrals; 99–121 subcaudals. Tail sometimes black.
Total length, 2,100 millimetres; tail 560.
Habitat: West Africa, from the Niger to Angola; Central Africa.
(3) D. angusticeps (The Mamba).—202–270 ventral scales; 99–121 subcaudals.
Colour green, olive, or blackish, uniform; belly yellowish or pale green; caudal scales and shields not bordered with black.
Total length, 2,000 millimetres; tail 430.
Habitat: West Africa, south of the Congo; Central Africa, East Africa, Transvaal, Natal.
(4) D. antinorii.—Scales in 21–23 rows; 248 ventrals; 117 subcaudals. Colour olive on the back, yellowish on the belly.
Total length, 2,690 millimetres; tail 545.
Habitat: Abyssinia.
II.—Viperidæ.
The African Viperidæ all belong to the Subfamily Viperinæ, of which the following are the seven principal genera:—
(a) Causus. (b) Vipera. (c) Bitis. (d) Cerastes. (e) Echis. (f) Atheris. (g) Atractaspis.
(a) Causus.
(Fig. 35.)
Head distinct from the neck, covered with symmetrical shields; nostril between two nasal shields, and the internasal; eyes moderate, with round pupils, separated from the lips by subocular shields. Body cylindrical; scales smooth or keeled, oblique on the sides, in 15–22 rows; ventral scales rounded. Tail short; subcaudals in 2 rows or single.
Four species:—
(1) C. rhombeatus.—Snout obtuse, moderately prominent. Scales in 17–21 rows; 120–155 ventrals; 15–29 subcaudals.
Colour olive or pale brown, usually with a series of V-shaped brown spots bordered with white, and a large spot in the form of a circumflex accent at the back of the head; lips bordered with black; belly yellowish or grey.
Total length, 700 millimetres; tail 75.
Habitat: Tropical and South Africa, from the Gambia to the Cape.
(2) C. resimus.—Snout prominent, more or less turned up; scales in 19–22 rows; 134–152 ventrals; 17–25 subcaudals.
Colour greyish-olive on the back; uniform white on the belly.
Total length, 470 millimetres; tail 40.
Habitat: Central and East Africa, Angola.
(3) C. defilipii.—Snout prominent, more or less turned up. Scales in 17 rows; 113–125 ventrals; 10–18 subcaudals.
Colour grey or pale brown above, with a series of large rhomboidal or V-shaped blackish-brown spots; a large A-shaped dark brown mark on the occiput; an oblique dark streak behind the eye; supralabial shields edged with black; belly yellowish.
Total length, 400 millimetres; tail 22.
Habitat: Central and East Africa, Transvaal.
Fig. 35.—Skull of Causus rhombeatus. (After G. A. Boulenger, op. cit.)
(4) C. lichtensteinii.—Snout obtuse; scales in 15 rows; 142–144 ventrals; subcaudals 15–21, single.
Colour greyish, with rather indistinct darker chevron-shaped cross-bands.
Total length, 413 millimetres; tail 35.
Habitat: West Africa (Gold Coast), Congo.
(b) Vipera.
(For the characters of this genus, see p. 23—Europe.)
In North Africa are found Vipera latastii, V. ammodytes, and especially V. lebetina, the range of which extends from Morocco to Northern India. Vipera superciliaris, which occurs on the coast of Mozambique, has the snout rounded, and the head covered with small, imbricate, keeled scales, with a large supraocular shield; nostril very large, between two nasal shields; scales on the body strongly keeled, in 27 rows; 142 ventrals; 40 subcaudals.
The colour is pale reddish-brown or orange, with blackish transverse bars broken by a longitudinal yellow band on each side; the belly is white, spotted with black.
Total length, 570 millimetres; tail 77.
(c) Bitis.
(Fig. 36.)
The Viperidæ belonging to this genus have the head very distinct from the neck, covered with small imbricate scales; the eyes rather small, with vertical pupils, separated from the lips by small scales; the nostrils directed upwards and outwards, usually pierced in a single nasal shield, with a rather deep pit above, closed by a valvular supranasal. The postfrontal bones are very large, in contact with the ectopterygoids. Scales keeled, with apical pits, in 22–41 rows; ventrals rounded. Tail very short; subcaudal scales in 2 rows.
(1) B. arietans (the Puff Adder; fig. 37).—This viper has the nostrils on the upper surface of the snout, and two series of scales between the supranasal shields; 12–16 supralabials; 3–5 lower labials. The scales on the body are in 29–41 rows, and strongly keeled; ventrals 131–145; subcaudals 16–34.
The body is thick, the head large and triangular, and the tail very short. The colour is dirty yellow or orange, with large, transverse or oblique, chevron-shaped black bands; an oblique black band extends behind the eye. The belly is dirty yellow, uniform, or marked with small black spots.
Total length, 1,350 millimetres, sometimes more; tail 160.
Fig. 36.—Skull of Bitis arietans (the Puff Adder). (After G. A. Boulenger, op. cit.)
Habitat: This snake is met with throughout Africa, from Southern Morocco, Kordofan, and Somaliland, to the Cape of Good Hope, and also in Southern Arabia. It is especially common near the Niger and on the Congo.
When irritated, it puffs itself out to such an extent that its body becomes twice the ordinary size. It then doubles back its head and neck in the shape of an S, and emits a loud and prolonged hiss. Before biting, it first strikes a blow with its head as with a battering-ram, thus justifying its French name, vipère heurtante (Striking Viper).
Fig. 37.—Bitis arietans (the Puff Adder). (After Duméril and Bibron.)
The natives of South Africa assert that this Viper is able to spring high enough to strike a rider on horseback. It feeds