SAURIA: GECKOTID^: AND CHAMELEONID^E. 297 



head short, rounded in front, and bordered at the sides 

 and behind with spines ; the body short, oval, much de- 

 pressed, with a dentated margin at the flank, and covered 

 above with three-sided tubercles arising from small imbri- 

 cated scales. Several Fig. 158. 

 species are found in 

 the central and western 

 parts of North America. 

 The Horned Toad, 

 P. cornuta, Gray, from 

 Missouri to Texas, is 



OVer four and a half Horned Toad, P. cornuta, Gray. 



inches long, ash-color, marked with yellowish and dark ; 

 abdomen and thorax silvery white with dusky spots. It 

 moves with rapidity upon the ground, but never climbs. 

 It is sluggish in confinement. 



GECKOTID^:, OR GECKO FAMILY. This Family com- 

 prises Saurians which have not the elongated, graceful 

 form of the preceding lizards, but are more or less flat- 

 tened, and their gait is a heavy kind of crawling. The 

 tongue is fleshy, and hot extensible ; their jaws are fur- 

 nished with a range of very small teeth ; and their toes 

 have a flattened disk, which enables them to move even 

 on walls and ceilings. Many genera and species are 

 known in the warmer parts of both continents. 



CHAMELEONIM:, OR CHAMELEON FAMILY. This Fam- 

 ily comprises lizards which have the body compressed, 

 skin roughened, tail round and prehensile, and feet five- 

 toed. The tongue is cylindrical, fleshy, and extremely 

 extensible ; teeth trilobate, and eyes large, but covered 

 with skin except a small hole opposite the pupil, and 

 possessing the faculty of moving independently of each 

 other. Their lungs are so enormous, that, when inflated, 

 their body seems to be transparent, a circumstance 

 which led the ancients to believe that these animals fed 

 13* 



