The Family Xanfusii'dae 



Xantusia vigilis were found at Fort Tejon, California, by Mr. 

 John Xantus, who furnished the three specimens upon which 

 Prof, liaird based his original description, published in the 

 Proceedings of the Academy of Natural Sciences of Philadelphia, 

 1858. Nothing more concerning it appeared until May, 1895, 

 when Dr. Stejneger recorded two specimens, secured by the 

 Death Valley Expedition in 1891. Nothing has been known 

 about its habits and this very interesting species has been con- 

 sidered one of the rarest of our reptiles. 



"Distribution. — In reality, X. vigilis is the most abundant 

 lizard in the territory it has chosen for its home. It seems to 

 be peculiarly dependent upon the presence of tree yuccas. A 

 glance at Dr. Merriam's map* shows that these weird plants 

 grow in each of the localities from which the species has been 

 recorded, viz.: Fort Tejon in the Canada de las Uvas, and Hes- 

 peria, in California, and Pahrump Valley, in Nevada. 



"Dr. Charles H. Gilbert and the writer collected speci- 

 mens near Mojave, and found a portion of a cast skin at Victor, 

 California, in November, 1893. In September of the following 

 year, the writer found this species common at Mojave and Hes- 

 peria, and secured a single specimen near Cabazon on the eastern 

 slope of San Gorgonio Pass, California. The first three of these 

 localities are situated in the great Yucca arborescens belt, which 

 extends along the southwestern edge of the Mojave Desert. The 

 last is in a small and apparently isolated grove of smaller tree 

 yuccas, seemingly of another species. 



"Habits. — Mojave, California, Nov. 4, 1893. About a mile 

 from the station, there is a considerable forest of Yucca arborescens. 

 The many trees and wind-broken branches, which lie decaying 

 on the ground, afford a home to numerous colonies of white ants, 

 scorpions, vicious-looking black spiders and several species 

 of beetles. In a deep crack of one of these branches a small 

 lizard was discovered which, when caught, proved to be a young 

 Xantusia vigilis. Probably it had not yet learned how to hide 

 from the day, for I have never seen another undisturbed individual. 



"The key to their home once discovered, the collection of 

 a large series of these lizards was merely a matter of physical 

 exertion. Fvery fourth or fifth stem that was examined gave 

 up its Xantusia, and in one instance five, as many as were pre- 

 viously known to collections, were found under a single tree. 



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