INTRODUCTORY NOTES. 513 



number are the grossest exaggerations, as very few were met with during 

 the expedition of 1872 (although in 1873 many were found along the Gila 

 in Arizona) ; probably not more than twenty individuals being observed 

 during a ride of over two thousand miles. Our experience also goes to show 

 that the rattlesnake is naturally timid and retiring instead of aggressive, as 

 efforts were frequently made to provoke them to strike without success, 

 they invariably gliding away if permitted. The collection of lizards is rich 

 not only in numbers but species, over one hundred specimens being secured, 

 embracing some twelve species, among which are three new ones belonging 

 to the genus Sceloporus. The collection of Batrachia is also numerous, and 

 contains some interesting individuals new to the localities visited as well as 

 new species. 



The collection of 1873 was made chiefly in Arizona, New Mexico, and 

 Colorado, and from its size and value reflects great credit upon those engaged 

 in securing it. Some of the specimens secured are extremely rare, and 

 many new facts in regard to distribution have been evolved from a study 

 of the material. 



During the season's work, it may be interesting to mention the finding 



of Crotalus lucifer, the Black Rattlesnake of Southern California and Arizona, 



as far north as the White Mountains of Arizona, in which locality it abounds, 



and Heterodon nasicus, the "Hog-nosed Sand Viper", as far south as Mineral 



Springs, Arizona. The coloration of this species of Heterodon, peculiar to 



the West, is much deeper and moi-e brilliant than its eastern congener. 



This serpent, which is entirely harmless, curiously enough (for there are no 



facts to warrant the belief) is esteemed as venomous, and greatly dreaded 



by settlers, who ruthlessly destroy it when occasion offers. This belief 



doubtless has originated from the fact of the presence of two fangs in the 



posterior part of the upper jaw, which, however, have no poison sacs attached. 



From the general appearance of this reptile, with its narrow, contracted 



neck, flat, broad head, stumpy tail, and peculiar teeth, we may readily infer 



the cause of the dislike exhibited by the settlers. Eutcenia vagrans was 



everywhere found exhibiting the same diversity of coloration and markings 



as heretofore, and the same remark will apply ecpially well to Pityophis sayi 



var. bellona. 

 33 z 



