18. CNEMIDOPHORUS 515 



"They were seen in copulation on June 10, and pairs 

 were commonly seen after this date. On June 21 one was 

 seen pursuing another, but whether this was for purposes of 

 play or was an exhibition of sexual instinct is not known." 



Mr. Camp states: "The whip-tailed lizard seems to 

 occur abundantly in the Turtle Mountain vicinity in every 

 phase of environment, except the rocky mesa, from rocky 

 hillside to sand dune (see table, p. 507). It was especially 

 well represented over the rocky hillsides, where individuals 

 ceaselessly forage, sticking their sharp noses into little piles 

 of leaves and debris or picking up small bits of food with 

 their active tongues. They slink about hesitatingly on the 

 sand, with their tails dragging behind them, thus leaving a 

 characteristic track. When running swiftly this lizard ele- 

 vates its tail, so that the ground is just cleared^ and the 

 tip lashes about as the lizard runs. 



"Though usually timid, the whip-tails, like Callisaurus, 

 seem to be almost devoid of fear when feeding. I saw two 

 come into a room and gather crumbs from the floor while 

 several people were about. They sometimes rest with their 

 hind feet raised clear of the hot sand. They exhibit a tend- 

 ency to burrow with their forefeet when annoyed." 



Mr. Pack gives the following observations on the method 

 of burrov/ing: "The floor of the cage in which these lizards 

 were kept was covered with sand to a depth of several inches. 

 Several medium-sized stones lay about on the sand. 



"Upon frequently finding the lizards in burrows of 

 their own construction, which extended from near the edge 

 of the rocks, and well underneath them, I made careful 

 observations to determine the method by which this feat was 

 accomplished. 



"The lizard began by scooping aside the sand with its 

 front feet. It used these feet alternately, one stroke only 

 being made by each foot at a time. Then, discontinuing the 



