282 BULLETIN 34, UNITED STATES NATIONAL MUSEUM. 



The cautbus rostralis uot marked, the muzzle descending very steeply 

 from the anterior angles of the orbits, shorter than the elevated perpen- 

 dicular extremity. Frontal ridges thickened, frequently partially filling 

 the median groove, higher than eyelids, and rising steeply backwards, 

 where they terminate in two short convergent tuberosities, with inte- 

 rior crenations. Occiput generally raised above the nape; postocular 

 ridge equally developed, sending a small angle to the anterior acumi- 

 nate extremity of the parotoids. Elevation of cranium at parietal tuber- 

 cle equal to length of same from the same point. Eyes large; tympa- 

 num distinct; half eye; parotoid narrow, long, acuminate at both ends. 

 Elbow to anterior margin of orbit ; heel to end of muzzle. Skin every- 

 where with numerous small tubercles ; soles rough; toes half webbed, 

 as in the other subspecies. The internal metatarsal tubercle is dis- 

 tinctly larger, i. e., wider, than in the other subspecies, almost equaling 

 that of the B. cognatus. The external tubercle is also larger than in 

 the other forms, but it never possesses a free cutting edge as it does in 

 the B. cognatus. The relative shortness of the head is expressed by the 

 measurement, one-fifth the length of the head and body. This charac- 

 ter is, however, not constant. Thus in the typical specimens of the spe- 

 cies (No. 2632, Canadian Ei ver) the head enters 4.66 times into the length. 

 The same is true of Nos. 14526 and 10195. In Nos. 4185 and 2646 the 

 head enters the length 4.5 times. In young specimens, as is usual, the 

 specific characters are not well marked, and the head is one-fourth the 

 length. This peculiarity is retained in a specimen, (No. 14,538) from 

 Saint Thomas, Nev., which is 3 inches in length. An exceptional state 

 of affairs is seen in two large specimens (No. 2651) from the head of the 

 Loup Fork River, Nebraska. The head is one fifth the total length, 

 and the supraorbital crests are parallel, as in typical specimens; but 

 the crests are well separated by a deep gutter behind, whose bottom is 

 not raised above the nape in the usual manner. 



Brown above, with pale vertebral line and three pairs of deep-brown 

 medium-sized spots, with paler centers. Sides and lips with small 

 brown spots. Femur and tibia with one indistinct brown cross-bar 

 each. Below uniform yellow. The thoracic region is sometimes black 

 speckled. 



This is the Rocky Mountain species, as B. cognatus is the species of 

 the plains. Its range does not appear to extend beyond the boundaries 

 of the United States. Its transition to the B. I. americanus is easil}^ 

 perceived in seven specimens collected at Pike's Peak by John Yarrow. 

 One of these is a true B. I. tcoodJiousei, while the other six can not be 

 separated from the B. I. americanus. Dr. Hallowell described a toad 

 under the name of B. dorsalis in Sitgreaves' report on the expedition to 

 Zuni and the Colorado River, p. 142, PI. 19. There is nothing in the de- 

 scription nor in the figure to enable us to ascertain what species or sub- 

 species is represented; The evidence is as much in favor of the speci- 

 men having been a B. I. americanus as a B. I. woodhousei, and no lo- 



