1916 ] Camp: Amphibians and BeptUes 529 



white lines on back of neck; back speckled with brown scales. Total 

 length S6 millimeters, tail length 52 millimeters. 



The specimen secured was found in the usual habitat of the species, 

 under a prostrate tree-yucca branch in a small grove of Yucca mo- 

 havt nsis. The species is rare in this locality, which appears to be the 

 eastern limit of its range. Unsuccessful search was made for night 

 lizards among the rather scattering tree yuccas along the east base of 

 the Turtle Mountains, five miles north of the Horn Mine. 



Cnemidophorus tigris tigris Baird and Girard 

 Desert Whip-tailed Lizard 



Fifteen individuals (nos. 5503-5517) of this forked-tongued lizard 

 were secured in the vicinity of the Horn Mine and Blythe Junction. 

 This series illustrates some phases of variation as pointed out by 

 Gadow (1906) for this remarkably unstable genus. The scales along 

 the edge of the gular fold are all smaller than those under the chin, 

 and are of equal size throughout. The number of large, transverse 

 scales in front of the forearm run from 6 to 9. The femoral pores are 

 19 in one thigh, 20 in five, 21 in six, 22 in nine, and 23 in seven of the 

 thighs in which counts could be made; being 23 right: 23 left twice, 

 23:22, J 1 22:23, J 1 22:22 three times, 22:—, 21:22, 21 :21, 20:21 three 

 times, 20 :20, and 19 : — . The femoral pores are large in four, medium 

 in six (at least two of which are males), and small in five specimens. 



Light, almost wholly unspotted, specimens were taken on the glar- 

 ing sand south of Blythe Junction. The throats in these are cream- 

 colored and much lighter than in other specimens; and the sides of the 

 head are yellowish and show no dark markings. Other specimens col- 

 lected among dark rocks, in washes, and on rocky hillsides exhibit the 

 bluish gray throats, dusky shoulders, and yellowish hind quarters typi- 

 cal of the species. The areas between the darker spots on the neck, 

 and the spot in front of the ear (light yellow in C. stejnegeri and in 

 C. tigris undulatus), are in the present series dusky, and in many speci- 

 mens this dusky suffusion obscures the darker markings on the sides 

 of the neck. The dorsal spotting, striping and cross-banding seems to 

 occur rather indiscriminately among both large and small individuals. 

 The examples from sandy areas, as before noted, have the dorsal pat- 

 tern almost obliterated. The dorsal black dashes in some of the others 

 are in six to eight longitudinal series joined obliquely to form zigzag 

 stripes, with the yellow ground color showing as longitudinal lines be- 



