592 ZOOLOGY REPTILES AND BATRACHIANS OF ARIZONA. 



sides of the head are quite red. The under parts vary from a plain dull 

 grayish-white to close nebulation with numerous squarish dusky spots. 

 The young are generally very light colored and more uniform than the 

 adults, a plain reddish or grayish brown prevailing on the upper parts. 

 The orbicular shape of the body appears constant, but there is a great dif- 

 ference in the length of the tail and its thickness at the base. It varies from 

 nearly half to considerably less than half the total length (contained If to 

 2 times in the total length). Specimens from the Colorado Chiquito River 

 are conspicuous by the yellow edging of the oval brown dorsal spots. 



This is the most widely distribiited species of the genus Phrynosoma (in- 

 cluding Tapaya and Doliosaunis) in the United States, and one of the most 

 abundant. I have recently ascertained its extension to British America in 

 the region of the Milk River, where it is a common animal. In these 

 higher latitudes, its dispersion seems strictly coincident with that of Caudi- 

 sona confluenta. In New Mexico and Arizona, it is the characteristic species. 

 I found it abundant at all points on my journey from Santa Fd, N. Mex., to 

 Fort Whipple, Ariz., and constantly met with it in various other parts of 

 the last named Territory. 



Like other species of the same genus, this Phrynosoma is slow of foot 

 and readily captured by hand ; it makes an interesting pet to one fond of 

 observing the traits of lower animals. It may readily be secured by a 

 thread tied behind the "horns"; and in this state of partial liberty its habits 

 may be studied to advantage. It is one of the most inoffensive and amia- 

 ble of reptiles ; though some of the largest and boldest individuals some- 

 times make a slight demonstration in self-defense by biting weakly, it 

 usually submits at once without remonstrance. When handled, it has a way 

 of making itself perfectly flat, when, closing its eyes, it will simulate death 

 in this collapsed state. Under some circumstances, it will swell up the body 

 prodigiously till it assumes a nearly spherical shape. It has a sly way of 

 watching for a chance to escape by bolting away when it thinks itself un- 

 observed, and a still more curious knack of burying itself in sand or other 

 loose soil. This is accomplished by a gradual lateral and forward insinuat- 

 ing wriggling of the body, with the muzzle pointed downward and the 

 limbs drawn close to the sides. A few moments suffice for its disap- 



