384 3. IGUANID.^ 



These blotches vary greatly in intensity but are almost 

 always edged posteriorly with white, gray, or yellow. There 

 is a distinct large dark blotch on each side of the neck. The 

 coloring of the tail is similar to that of the back. The 

 ground color of the head is very variable, but it often is 

 pinkish or yellowish olive, the temporal regions pink or red. 

 The entire lower surface is white or pale yellow, often 

 clouded or spotted with gray or slate. 



Remarks. — In regard to the relations of this subspecies 

 see remarks under P. d. douglassii and P. d. ornatlsshnmn. 

 On comparing series of horned-toads from Arizona and 

 Utah much variation is found in both. The head seems 

 not more pointed in one series than in the other; its lateral 

 outline is variable and may be straight, slightly convex or 

 slightly concave. The head-spines average larger and 

 longer in the Arizona series, in which also the temporals 

 and occipital horns occasionally are erect in P. d. hernandesl, 

 even in specimens from as far south as the Huachuca Moun- 

 tains. There is a good deal of variation in the shape of the 

 occipital angle and space. The occipitals usually are nearer 

 the temporals in Arizona specimens than in those from 

 Utah, but the difference is only an everage one. There 

 seems to be an average difiFerence in the interval between 

 the apex of the occipital angle and the base of an occipital 

 horn, Arizona specimens {hernandesi) usually having only 



