698 Bulletin American Museum oj Natural History [Vol. XL VI 



The presence of this species on San Esteban is further indication of 

 the Sonoran, not Lower Calif ornian, character of its fauna; and this 

 conclusion is quite independent of the possibility that further adult 

 specimens from San Esteban might justify the description of an insular 

 race. 



Crotalus tortugensis Van Denburgh and Slevin 



Crotalus tortugensis Van Denburgh and Slevin, 1921c, p. 398 

 Range. — Tortuga Island, Gulf of California. 



Crotalus oreganus Holbrook 



Crotalus oreganus Holbkook, 1840, p. 115, PL xxix. 

 Crotalus oregonus Stejneger and Barbour, 1917, p. 110. 



Range. — British Columbia to northwestern Lower California. 



Lower Californian Records. — Los Coronados Islands, Streets, 1877, p. 40; 

 " 75 miles S. E. of San Diego," Lockington, 1880, p. 295; San Pedro Martir Mt., Van 

 Denburgh ; 1896, p. 1007; San Jose, Meek, 1905, p. 17. 



A specimen in the Biological Survey collection, U. S. N. M. No. 

 37575, is from La Grulla. 



Crotalus atrox atrox Baird and Girard 



Crotalus atrox Baird and Girard, 1853, p. 5; Stejneger and Barbour, 1917, p. 108. 



Range. — Texas and northern Mexico to southeastern California, entering north- 

 eastern Lower California. 



Lower Californian Records. — East side of Cocopah Mountains, Murphy, 

 1917, p. 57. 



I have no hesitation in recording this species from Lower California 

 on the basis of the verbal record above quoted, as there is no snake in 

 this area with which Crotalus atrox could readily be confused. 



Crotalus atrox lucasensis Van Denburgh 



Crotalus lucasensis Van Denburgh, 1920a, p. 29, PI. in. 



Range. — Southern Lower California. 



Lower Californian Records. — Cape St. Lucas, Cope, 1861, p. 292; La Paz, 

 Yarrow, 1882, p. 75. San Jose del Cabo, Sierra El Taste, Van Denburgh, 1895, p. 156; 

 Santa Rosalia, San Ignacio, Mulege, Mocquard, 1899, p. 332. 



Six specimens of this species were collected by the Albatross Expedi- 

 tion at Mirafiores (A. M. N. H. Nos. 5596-97, 5644-45, U. S. N. M. No. 

 64589) and head of Concepcion Bay (A. M. N. H. No. 6883). They agree 

 with Van Denburgh's description in having the dorsal rhombs distinctly 

 outlined laterally. 



The dorsal scales range from 35-27-23 to 31-25-21. The ven- 

 trals range from 182 to 188 in four males, 189 and 195 in the two females; 

 subcaudals 25 to 29 in males, 21 in both females. There are three black 



