916 16. CROTALID& 



Description. Large. Head broad, flat-topped, varying 

 in outline according to position of fangs. Rostral usually 

 higher than wide, in contact with anterior nasal. Two nalals. 

 Usually two preoculars and two to four internasals. A 

 large scale just in front of supraocular. Supraocular large 

 but not raised into a horn-like process} separated from its 

 fellow by from three to six irregular rows of scales. About 

 13 to 17 superior and 14 to 18 inferior labials; first pair 

 of latter usually meeting on median line in front of a single 

 pair of genials, but rarely divided. About three to five rows 

 of scales between supralabials and eye. Scales in 25 to 27 

 rows, of which one or two on each side are smooth. Gas- 

 trosteges varying from 179 to 191. Urosteges 17 to 27. 



The general color is yellowish or grayish brown, with a 

 series of large, darker brown blotches along the back. These 

 blotches often are not well defined, usually are not com- 

 pletely enclosed in light borders, and show much of the 

 punctulate or pepper-and-salt style of coloration. The sides 

 are more or less indefinitely spotted or blotched with dark 

 brown in the same punctulate manner, and sometimes show 

 pinkish shades. The head is nearly unicolor above or 

 mottled with darker. A yellowish or whitish stripe runs 

 across the side of the face from the preocular plates to the 

 mouth. The scales behind and above this light stripe are 

 darker than the ground color and are set off posteriorly by 

 a light streak which runs down and back from the corner of 

 the eye and strikes the supralabials in front of the corner of 

 the mouth. The tail is whitish or grayish with about four 

 to six black cross bands or rings. The lower surfaces are 

 yellowish white. 



Length to anus 840 870 975 1000 1060 1280 



Length of tail to base 



of rattle.... .55 65 65 83 82 102 



