THE PRINCIPAL SPECIES OF POISONOUS SNAKES 129 



Colour greyish-yellow to salmon-red, finely punctulated with 

 brown, with a dorsal series of transverse darker spots ; belly 

 yellowish. 



Total length, 1,020 milhmetres ; tail 90. 



Habitat : Desert regions of Southern California, Lower Cali- 

 fornia, and Arizona. 



(8) C. triseriatiis. — 9 — 13 supralabials ; scales in 21 — 25 rows, 

 dorsals strongly keeled ; 142 — -184 ventrals ; 22 — 30 subcaudals. 



Colour olive or brown, with a vertebral series of rather small 

 dark brown spots edged with black and white ; belly yellowish, 

 spotted with dark brown, or dark grey-brown powdered with 

 whitish. 



Total length, 530 millimetres ; tail 55. 



Habitat : Mexico. 



(9) C. pohjstictiis. — Closely allied to the foregoing, but 4 inter- 

 nasals, 14 or 15 supralabials, and scales in 27 — 30 rows ; 123 — 151 

 ventrals ; 18 — 23 subcaudals. 



Colour yellowish-brown, beautifully marked with 6 or 7 longi- 

 tudinal 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 

 9 



