410 REPORT OF NATIONAL MUSEUM, 1898, 



terniiiiatiug above posterior to the axilla. A single ])romiuent scale 

 above the Immeriis. A series of conic scales on each side of the tail, 

 which are not so prominent as the large keeled sj)inous scales which 

 project from among the flat ones of its superior surface. Superior face 

 of arm and cubitus covered with large acute keeled scales; of leg and 

 thigh with smaller scales, among which large prominent keeled and 

 spinous scales are mingled. Scales of inferior surfaces smooth, except 

 those of the distal part of the cubitus, the distal half of the tail, and 

 of the palms and soles, which are keeled. Lateral digital scales not 

 produced. 



Tlie legs are shorter than in any other North American species, the 

 posterior ones when extended reaching barely three-fourths the dis- 

 tance to the axilla. The tail varies in length in the subspecies from 

 about twice the head in the tyj^ical form to more than three times in 

 the subspecies hernandesii. Femoral pores, sixteen on each thigh, the 

 series approaching but not meeting on the middle line. 



Measurements. — Total length, 111 mm. ; length to vent, 80 mm. ; length 

 to gular fold, 19 mm. ; length of head with occipital horn, 19 mm. ; length 

 of head without a horn, 17 mm.; width at temporal region, 23 mm.; 

 length of fore leg, 32 mm.; length of fore foot, 11 mm.; length of hind 

 leg, 40 mm.; length of hind foot, 19 mm. 



The ground color of the superior surface of this species is variable 

 and under the control of the animal in a large degree. It may be pale, 

 ashy, brown, reddish, or nearly black. There is no distinct vertebral 

 stripe. There is a large dark nuchal spot on each side and three double 

 dorsal spots on each side of the body. These spots may be separate 

 or fused, in the latter case forming a cross baud with posterior bilobate 

 outline. They are ill defined anteriorly, but posteriorly they are well 

 defined, and frequently have a i^ale or even bright colored border. 

 Tail and limbs obscurely cross-banded above; head uniform brown. 

 Inferior surfaces uniform cream-colored, unspotted, except on the gular 

 region, where small black spots are frequently i)resent. The small 

 cranial horns are frequently pink. 



This species has much the most northern range of all the Phrynoso- 

 mas, inhabiting Oregon, parts of Washington, and Montana. To the 

 eastward it extends into Montana, Nebraska, and Kansas, and to the 

 south to Soccoro, New Mexico, and middle Arizona. It does not occur 

 in Texas, so far as known. It is thus especially characteristic of the 

 central region and the northern i)art of the Pacific. Within this range 

 it ijresents three modifications. Specimens from the northern Pacific 

 region are of smaller size than those from the Central region, and the tail 

 is short ; a larger brighter-colored and also short-tailed form from the 

 deserts of the great basin, and a larger and long-tailed form from the 

 Rocky Mountain region and eastward. 



