450 REPORT OF NATIONAL MUSEUM, 1893. 



Variation. — Beyond the usual iudividual variation in number of scale 

 rows, loveals, labials, size of scales on top of head, etc., nothing special 

 has been noticed in the material examined. The color varies from 

 whitish to tawny. The head markings are rather indistinct, especially 

 the postocular stripe, which is often lost in the dense si)rinkling of 

 minute black dots covering the sides of the head. 



Geographical distrihution. — This rare snake was formerly only known 

 from a few localities in southern Arizona near the Mexican boundary, 

 until in 1891 the Death Valley exploration under Dr. Merriam extended 

 its range very materially into the desert mountains of southern Cali- 

 fornia and Nevada south of the thirty-seventh parallel, from Owens 

 Valley to the Great Bend of the Colorado, where these snakes Avere 

 found to be quite common, as Dr. A. K. Fisher and his party killed no 

 less than nineteen in or near Shepherd Canyon, Argus Range, Califor- 

 nia, during the latter part of April and first week of May, 1801 The 

 vertical range is considerable, as Dr. Merriam's party collected speci- 

 mens at altitudes varying between about 2,000 and 0,500 feet above the 

 sea. 



Habits. — The Tiger Eattler which has received its name, not from any 

 extreme degree of bloodthirstiness or fatal aggressiveness, but from its 

 tawny color and marked cross stripes, seems partial to the barren moun- 

 tain ranges with their rocks and crevices in preference to the desert 

 valleys surrounding them. It is one of the smaller species and com- 

 paratively harmless, though, of course, a bite when inflicted might be 

 serious enough. 



During the Death A'alley expedition under Dr. C. Hart Merriam, a 

 specimen was found in a wood rat's nest that was dug open. Its stomach 

 contained a kangaroo rat {Dipoclomys) and a pocket mouse {Pero(/ita- 

 thns), indicating nocturnal habits. 



Mr. Stephens, of the same party, on April 15, 1891, killed a pair of 

 these snakes which were on a ledge of rock, standing erect with their 

 heads near together, " apparently playing." They were probably pur- 

 suing their amours, and the time would thus indicate the XJairing season 

 of the species. 



The Hokned Rattlesnake. 



Crotalvs cerastes,* Hallowell. 



Plate 15. 



1854. — CrotaJus cerastes, Hallowell, Proc. Pbila. Acad., 1854 (p. 95). — Hallo- 

 well, Pac. R. R. Rep., x, Williamson's Route (p. 17) (1859). — Baird, 

 U. S. Mex. Bound. Surv., ii, Rept., p. 14 (1859).— Baird Pac. R. R. Rep., 

 X, Reptiles, p. 16 (1859).— Cope, Proc. Pliila. Acad., 1859, p. 337.— Cope, 

 Bull. U. S. Nat. Mus., No. 1, Check-list, p. 33 (1875).— Cope, in Wheeler's 

 Surv. W. 100 Mer., v, p. 534 (1875).— Cope, Proc. U. S. Nat. Mus., xiv, 

 1891, No. 882, p. 694 (1892).— Jan, Elenco Sist. Ofid., p. 124 (1863).— 



* From the Greek Kspaorric (kerastes) in allusiou to the cerastes, or horned serpent 

 of the deserts of Northern Africa. 



