424 LOWER VERTEBRATES. 



by its having no auditory aperture, and it is a much more stumpy as well as a smaller 

 animal. There are no teeth on the palatine bones ; a fold of skin crosses the pectoral 

 region, and only femoral pores are present. JT. maculata is rather short and thick ; 

 more so in the female than male, the entire length being between three and four 

 inches. The tympanum is covered by scales similar to those of the neck. Running 

 across the lower jaw from the angles is a fold of skin, smaller though parallel to the 

 second or pectoral. The general color is olivaceous brown, passing into dim violet 

 on the sides of the head, and ornamented on the back and sides by dark-brown 

 blotches. 



Holbrook's lizard is found in the central and southern portions of the west, where 

 it inhabits the burrows of the prairie dog, Arctomys ludoviciana. H. propinqua and 

 texana are more limited in their distribution, being only found in Texas and the 

 neighboring portions of Mexico. 



We now come to the more depressed members of the family, which, having the 

 legs short and appended more to the sides, give the animals a toad-like appearance. 

 They are mostly terrestrial, hiding in pits and holes of the ground, usually selecting 

 stony and sandy localities. 



Few lizards are better known as objects of curiosity than those popularly called, 

 at home and abroad, ' horned or California toads.' From their odd appearance they 

 at once attract attention ; and liaving a most quiet disposition, seldom offering to bite, 

 and soon becoming accustomed to domestic life, they are seized upon as pets by trav- 

 elers, and have even been used as jeweliy, being tethered by a slender chain to a 

 breast-pin. Not only are they interesting from their habits while domesticated, but 

 many of their ways in nature are strange and unusual. There are no less than nine 

 different species of these animals inhabiting the country west of the Mississippi, from 

 Mexico to Dakota, all being included under the single generic title Phrynosoma, indica- 

 tive of their toad-like appearance. No genus of the order is more easily recognized 

 than this. The body is more or less circular in outline, extremely depressed, and cov- 

 ered above with spine-like scales, which extend on to and cover the short conical tail. 

 The solid sub-triangular head is jarovided with carina over the eyes, which are thus 

 placed in a groove and are minute. Strong horny spines are often developed from the 

 superciliary and temporal regions, as well as across the occiput. The pyramidal scales 

 of the back are greatly developed in P. cornuta, an animal which presents a most rough- 

 ened and spiny appearance. In P. jylMyrhinos and modestum the body is quite 

 smooth, and destitute of the roughness generally characteristic of the group. The 

 scales of the lower side of the neck and body are important in characterizing the sev- 

 eral species. On the breast and anterior portion of the shoulders the largest scales 

 appear, being here very prominent, acute posteriorly, and provided with strong ridges 

 or keels. The relative portions of the thighs are similarly protected, though with 

 much weaker scales. The legs are of about equal size, and used not for jumping, but 

 for running ; the popular name " toad " being given more because of the animal's gen- 

 eral appearance than from any relation to the Batracliians. Though the anal pores ar'e 

 absent, those of the thighs are present, and of different numbers in the sevei-al species. 



Phrytiosoma douglassi is wide-spread over the entire western plains, extending its 

 habitat from British America into Mexico, and presenting two accepted varieties ; the 

 coloring of different individuals from different localities shows considerable varia- 

 tion, ranging from a uniform brown shade above, to a spotted or barred ornamen- 

 tation ; infrequently the sides of the head are red. Below, the color may be of a 



