428 CALIFORNIA ACADEMY OF SCIENCES [Proc. 4TH SER. 
16, preocular 2—2, postoculars 3-3, loreal 1-1, dark markings 
on body are 26 rhombs and 12 cross-bars to anus, 4 black 
bands on tail. 
81.—Crotalus oregonus Holbrook 
We have three Arizonan specimens of the Pacific Rattle- 
snake. One is a young specimen (No. 35237) from Oak 
Creek, Coconino County, Sept. 2, 1912. The coloration of 
head, body, and tail is perfectly typical of this species. The 
scales are in 23 rows, gastrosteges 165, anal entire, urosteges 
24, supralabials 15-15, infralabials 15-15, preoculars 2-2, 
postoculars 3-3, loreals 1-1, dark dorsal markings on body 38. 
No. 17539, is a large adult secured at Cave Creek, Maricopa 
County, May 1, 1910. Its head is unicolor above and on 
sides, dark brown without any trace of markings. The dorsal 
rhombs are somewhat indistinct, and number 33 on the body 
to the tail, which bears six brown cross-bars. The lower sur- 
faces are mottled with brown. The scale rows are 25, 
gastrosteges 170, anal entire, urosteges 24, supralabials 15-15, 
infralabials 14-15, preoculars 2—2, postoculars 3-3, loreal 1-1. 
No. 34683, caught at an altitude between 7000 and 8000 
feet at the Wilderness of Rocks, on Mt. Lemon, Santa Cata- 
lina mountains, Pima County, June 12, 1912, has dorsal 
rhombs solid jet-black without lighter centers, but separated 
from each other by bright sulphur yellow edgings. The sides 
are brownish drab with dark brown markings and a few scat- 
tered yellow scales. The lower surfaces are yellowish white 
marbled with dark brown. ‘There are eight dark brown rings 
on the tail, separated by narrow dark gray intervals. The 
head markings are as in typical C. oregonus. Scale rows 25, 
gastrosteges 170, anal entire, urosteges 25 one divided, supra- 
labials 16-16, infralabials 15-15, preoculars 2—2, postoculars 
3-3, loreals 1-1, dorsal rhombs to tail 31. 
When we reached Tucson we heard much of the black rattle- 
snake of the Catalinas, as this species is locally known. It 
was with much difficulty that we secured a specimen (No. 
34683). There can be no doubt that it is specifically identical 
with C. oregonus of California. Whether it will be necessary 
to regard the dark Arizona snakes as a subspecies, C. oregonus 
cerberus (Coues), cannot be decided until more specimens are 
