114 BARBOUR — A NEW HORNED-TOAD [^V^i^VlP 



(lifFors conspicuously in having; much smaller and much more 

 rugose frontal scales; in having the head spines directed back- 

 ward along the shoulders, not upward at all; in having the 

 temporal regions covered with small rugose scales, instead of 

 larger scales which are almost smooth. The groups of enlarged 

 gular scales are very different. In blainvillii the outer row of 

 each of the enlarged group of four rows is but slightly greater in 

 size than the third, while the second and first, or mediad rows, 

 diminish in size each in similar slight degree. In schmidti, how- 

 ever, all the enlarged rows are smaller, the fourth or outer row, 

 however, being very much larger than the other three rows which 

 are more nearly the same size. In schmidti the ventrals are 

 smaller, averaging about 55 across the belly, while in hlainvillii 

 they number usually 40 or 41. 



The most conspicuous difference, however, is by no means easy 

 of exposition. In the mainland horned-toad the large postorbital 

 spine is connected with its fellow of the opposite side by a dis- 

 tinct row of enlarged, slightly spinose, scales; between these 

 and the row formed by the large posterior temporal and occipital 

 spines is an area occupied medially by three large, rather spinose 

 scales and a small spine which projects backward between the 

 occipitals. In the island form the postorbital spines are obso- 

 lescent; the intermediate region between the two blunted post- 

 orbital spines is composed of rather small, quite irregular, 

 rugose scales; so also is the region just anterior to the great 

 head spines. The latter is covered with a number of small, 

 irregular, corrugated scales, although there is a short spine, 

 more triangular than in hlainvillii, between the occipitals. 



The squamation of the body and limbs offers no conspicuous 

 diagnostic characters. The color, however, differs constantly. 

 In Schmidt's horned-toad the dark nuchal patches are much less 

 extensive than in the form named for Blainville, while the gen- 

 eral dorsal coloration is apparently darker, the blackish cross-bars 

 being very narrow and inconspicuous, whereas in the mainland 

 species they are invariably broad and conspicuous. 



