34 VENOMOUS SNAKES AND THE PHENOMENA OF THEIR VENOMS 



divided nasal. Body cylindrical; scales keeled, with apical pits, in 27 to 37 rows, 

 dorsal scales forming straight longitudinal series; ventrals rounded. Tail short; 

 subcaudals single. Africa, north of the Equator, southern Asia. 

 Echis carinatus. (Plate 14, b.) 



"Phoorsa"^ is characterized with a single row of subcaudal scales. It is fero- 

 cious and aggressive, ready to strike at any time. The body is of more or less dark 

 grayish color and is patterned with stripes and with speckles and dots of blackish- 

 brown; the back is marked with long whitish-yellow undulatory lines, on each side 

 of the vertebral line; the head has Y-shaped speckles. The scales produce a peculiar 

 noise, when the snake rubs them together by folding the body. Length reaches 

 2 feet. India, Persia, Beluchistan, Arabia, Palestine, and Africa, north of Equator. 

 Echis coloratus. 



The scales on the muzzle are convex and smooth or slightly keeled. No Y mark 

 on head. Length 2.5 feet. Arabia, Socotra, Palestine. 



Genus ATHERIS Cope. 



Head very distinct from neck, covered with imbricate scales. Eyes large, 

 vertical pupils. Body slightly compressed. Scales keeled, with apical fossa. 

 Tail moderate and prehensile, subcaudals in one row. Arboreal habits. Tropical 

 Africa. 



Atheris chlorechis. 



Color greenish with small yellow dots, end of tail yellow. Length about 1.5 

 feet. Western Africa, from Liberia to Ogowe. 



Athens squamiger. 



Color olive, with yellow, narrow, more or less regular Y bands, or with green 

 spots; belly dark olive with black spots. Length about 1.8 feet. Western Africa, 

 from Cameroon to Angola. 



Atheris ceratophorus. 



Many erectile superciliary scales. Body highly keeled. Dark olive color, with 

 cross-shaped black spots; belly pale olive. Length only 7 inches. Western Africa. 



Genus ATRACTASPIS Smith.2 (Plate 13, a, b, c.) 



Enormously developed poison fangs. A few teeth on palatine, but none on 

 pterygoid bones characterize this genus. The mandible edentulous, with 2 or 3 

 small teeth in middle of dentary bone. Head small and indistinct from neck. Eyes 

 minute, round pupil. No postfrontal bone. Body cylindrical; scales smooth, in 

 17 to 37 rows. Ventrals rounded off. Tail short, subcaudals in one or two rows. 

 General coloration brown, brownish-black, and black. This genus is remarkable 

 as presenting the most extreme speciahzation in the viperine direction, the poison 

 fangs being as large in proportion as in any other form and the solid teeth on the 

 palate and mandible, which are much reduced in number in many of the Crota- 

 lines, having almost disappeared. 



The habitats of the several species of Atractaspis and the variations in length are 

 shown in the following list: 



A. hildebrandii, length 1.5 feet; eastern Africa. 



A. congica, length 1.5 feet; Congo, Angola. 



A. irregularis, length 1.66 feet; central and western Africa from Gold 

 Coast to Congo. 



A. corpulenta, western Africa, from Liberia to Gaboon. 



A. rostrata, length 2 feet; central and eastern Africa. 



1 "Phoorsa" of the Hindoos; Efa or "Pyramid viper" of the Egyptians. 



2 This genus is given family rank in Cope's system as Atractaspididae. 



