The Horned Lizards 



and nothing could induce the lizard to open them. Within 

 two minutes after it was placed on the ground the protruding 

 aspect of the eye-balls and the swelling of the eye-lids had dis- 

 appeared. 



Most surprising was the amount of blood expended. The 

 wall and floor showed a course of thickly-sprinkled spots about 

 one eighth of an inch in diameter. There were 103 of these spots. 



In captivity the Horned Lizards are highly interesting and 

 will long survive if properly cared for. They require a screen 

 cage, of fair dimensions, with several inches of fine sand (building 

 sand) and must be kept dry and very warm. A flood of sun- 

 shine, for the greater part of the day, is absolutely necessary 

 to keep them in good health and feeding. Without the sun 

 they exhibit a general lassitude and feed indifferently. Water 

 should be given them in very shallow dishes, sunk in the sand, 

 but care should be taken in filling these that the sand itself is 

 not moistened. Mealworms, which may be obtained at any 

 bird store, form a good food, but specimens are also fond of ants, 

 small, soft-bodied grubs, roaches, grasshoppers and crickets. 

 They will not eat earthworms. 



A key to the genus follows: 



Division I. Head spines rudimentary or small represented 

 by mere tubercular scales, or spines that are little longer 

 than the horizontal diameter of eye-opening. 

 Area inside of the two large rows of plates on chin, com- 

 posed of small, uniform scales, 

 a. Ear drum exposed. 



f A single row of spiny, marginal scales on body. 

 Head spines reduced to tubercles, or with some 

 varieties, spines that are shorter than the diameter 

 of the eye. 



DOUGLASS'S HORNED "TOAD," P. dou^lassii and varieties. 

 Central head spines about equal in length to the hori- 

 zontal diameter of eye-opening. 



MEXICAN HORNED "TOAD," P. orbiculare. 

 ft No fringe of spiny scales on sides. 

 Central head spines about length of diameter of eye- 

 opening. Abdominal scales smooth. 



LITTLE HORNED "TOAD, " P. modestum. 



No head spines. Head very wide and flat at the tem- 

 ples, with ridges forming crown-like process above. 

 Abdominal scales keeled. 



DITMARS'S HORNED "TOAD," P. 



146 



