502 viPEErDA 



Head very distinct from neck, covered with small juxtaposed or 

 feiebly imbricate scales ; eye moderate or small, with vertical pupU, 

 separated from the labials by small scales ; nostril directed upwards- 

 and outwards, in a small single or divided nasal. Body cylindrical ;. 

 scales keeled, with apical pits, in 23-35 rows ; dorsal scales forming 

 straight longitudinal series, with club- or anchor-shaped keels not 

 extending to the extremity of the scale ; lateral scales smaller, 

 oblique, pointing downwards, with serrated keels ; ventrals with an 

 obtuse keel on each side. Tail short ; subcaudals in two rows. 



North Africa, Arabia, Palestine. 



1. Cerastes cornutas^ q^^.O'-*'^'"^ ^ 



Coluber comutus, Linn, in Hasselq. Reise PaUest. p. 315 (1762). 



cerastes, Linn. 8. N. i. p. 876 (1766) ; Ellis, Phil. Trans. Ivi, 



1767, p. 287, pi. xiv. ; Shaw, Nat. Miscell. iv. pi. cxxii., and ZooL 

 iii. p. 385, pi. ciii. (1802). 



Cerastes comutus, Forsk. Descr. Anim. p. ix (1776) ; Bouleng. Trans, 

 Zool. Soc. xiii. 1891, p. 165 ; Werner, Verh. zool.-bat. Oes. Wien, 

 xliv. 1894, p. 86. 



Vipera cerastes, Latr. Mept. iii. p. 313, pi. — . fig. 2 (1802) ; Baud, 

 Pept. vi. p. 178, pi. kxiv. fig. 1 (1803) ; L Geoffr. Descr. Egypte, 

 Mept. p. 155, pi. vi. fig. 3 (1827) ; Schleq. Phys. Serp. ii. p. 686, 

 pi. xxi. figs. 12 & 13 (1837) ; Strauch, Er'p. Alg. p. 72 (1862), and 

 Syn. Viper, p. 108 (1869) ; Jan, Icon. G^n. 45, pi. v. fig. 1 (1874), 



Cerastes hasselquistii, Gray, Zool. Miscell. p. 70 (1842), and Cat. 

 p. 28 (1849) ; Tristram, Faun. Pakst. p. 147 (1884). 



Echidna atricauda, part., Bum. ^ Bibr. vii. p. 1480 (1854). 



Cerastes segyptiacus, Bum. ^ Bibr. t. c. p. 1440, pi. Ixxviii. b. fig. 3. 



Vipera avicennse, part., Jan, I. c. fig. 3. 



Snout very short and broad. Rostral small, twice to thrice as 

 broad as deep ; head covered with small tubercularly keeled scales 

 of unequal size above, 15 to 21 across from eye to eye ; a large, 

 erect, ribbed, horn-like scale often present above the eye ; 14 to 18 

 scales round the eye ; 4 or 5 series of scales between the eye and 

 the labials ; nostril in a single small shield, separated from its 

 fellow by six to eight longitudinal series of scales and from the 

 rostral by two or three (rarely one) ; 12 to 15 upper labials ; three 

 lower labials in contact with the chin-shields. Scales in 27-35 

 rows. Ventrals 130-165, with very feeble lateral keel ; anal entire ; 

 snbcaudals 26-42, the posterior usually more or less distinctly keeled. 

 Pale yellowish brown or grey above, with or without brown spots, 

 forming four or six regular longitudinal series, the two middle ones 

 sometimes confluent, forming cross-bars ; a more or less distinct 

 oblique dark streak behind the eye ; lower parts white ; end of tail 

 sometimes black. 



Total length 720 miUim. ; tail 90. 



Northern border of the Sahara, Egypt, Nubia, Arabia, Southern 

 Palestine. 



a, S (Sc. 30 ; V. 133 ; Biskra. J. Brenchley, Esq. [P.], 



C. 29). 



