424 LOWER VERTEBRATES. 



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

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

 region, and only femoral pores are present. IT. 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. 



Ilolbrook'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. propinqiai 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 shoi't and aj^pended more to the sides, give the animals a toad-like ajjjjearance. 

 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 ]iopularly called, 

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

 at once attract attention ; and having 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 jewelry, 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 iidiabiting the country west of the Mississippi, from 

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

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

 than this. The body is more or less circidar 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 provided with carina over the eyes, which are thus 

 placed in a groove and are mimite. 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 sjjiny appearance. In P. platyrhinos and modesttitn 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 jiosteriorly, and provided with strong ridges 

 or keels. The relative portions of the thighs are similarly ])rotected, though with 

 nnich 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- 

 ei-al ajij)earance than from any relation to the Batrachians. Though the anal pores are 

 absent, those of the thighs are present, and of different numbers in the several species. 



Phrynosoma douglussi is wide-sjiread over the entire western plains, extending its 

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

 coloring of different individuals from different localities shows considerable varia- 

 tion, ranging from a imiform brown shade above, to a s]iotted or barred ornamen- 

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



