48. CROTALUS 951 
Merid., Appendix NN, 1878, p. 210; Yarrow, Bull. U. S. Nat. 
Mus., No. 24, 1883, pp. 12, 73; Townsenp, Proc. U. S. Nat. Mus., 
Vol. XIII, 1890, p. 144; SrEyNEGER, West Amer. Scientist, Vol. 
VII, 1891, p. 165; Cope, Proc. U. S. Nat. Mus., Vol. XIV, 1892, p. 
694. 
Crotalus confluentus var. pyrrhus Garman, Mem. Mus. Compr. Zool., 
Cambr., Vol. VIII, No. 3, 1883, p. 173. 
Crotalus oregonus var. mitchelli Garman, Mem. Mus. Compr. Zool., 
Cambr., Vol. VIII, No. 3, 1883, p. 173; Garman, Bull. Essex 
Inst., Vol. XVI, No. 1, 1884, p. 35. 
Crotalus Mitchellit pyrrhus STEJNEGER, Report U.S. Nat. Mus. for 1893, 
1895, p. 456. 
Description—Moderately large. Head rather small, 
with flattened top, varying in outline according to position 
of fangs, etc. Rostral either higher than wide or wider 
than high, separated from anterior nasal by one to two rows 
of granular scales. Usually two nasals, and two preoculars. 
Postoculars usually three, sometimes four. Supraocular large, 
somewhat projecting laterally, separated from its fellow by 
from four to eight scales. Thirteen to 18 superior and 14 
to 18 inferior labials, first pair of latter meeting in front of 
a single pair of genials. Three to five rows of scales between 
supralabials and eye. Scales in 23 to 27 rows, keeled except 
sometimes in one or two rows of each side. Gastrosteges 
varying from 158 to 198. Urosteges 16 to 27, a few of 
the posterior sometimes divided. 
The general color is white, gray, yellow, vinaceous-cin- 
namon, or salmon-red, minutely dotted with black or brown, 
and with a series of about 32 to 37 indefinite brown, black, 
or red blotches along the back anterior to tail. These dots 
and dorsal blotches, as well as smaller blotches which some- 
times are present on the top of the head and on the sides, 
may be so faint as to cause the animal to be called the White 
Rattlesnake, or so dark as to produce a blackish effect; the 
blotches, however, never have definite outlines, appearing 
