Total length, 1,320 millimetres; tail 130.
Habitat: Arizona, New Mexico, and Texas to Southern Brazil, and Northern Argentina.
(2) C. scutulatus (Texas Rattle-Snake; [fig. 74]).—13-16 supralabials; scales in 25 or 27 rows; dorsals striated and strongly keeled; 167-170 ventrals; 18-20 subcaudals.
Colour yellowish or greyish-brown, with a series of large dark brown light-edged rhomboidal spots; an oblique dark streak below the eye; belly uniform yellowish-white.
Total length, 760 millimetres; tail 65.
Habitat: Arizona, New Mexico, Texas, North Mexico.
(3) C. confluentus (Pacific or Mottled Rattle-Snake; [fig. 75]).—Upper head-scales small, striated; 13-18 supralabials; body scales in 25-29 rows, striated and strongly keeled; 168-197 ventrals; 17-34 subcaudals.
Colour yellowish, greyish, or pale brown, with a dorsal series of large brown or red spots, usually rhomboidal or transversely elliptic in shape; a light streak or triangular marking across the supraocular shields; belly yellowish, uniform or spotted with brown.
Total length, 1,520 millimetres; tail 140.
Habitat: Western North America, from British Columbia to South California, eastwards to Assiniboia, Dakota, Nebraska, Kansas, and Western and Southern Texas; Northern Mexico.