42 



BULLETIN 160, UNITED STATES NATIONAL MUSEUM 



Type locality. — Arkansas River, Prowers County, Colo. 

 Range. — In Mexico the range of tliis toad extends southward from 

 the northern boundary to San Pedro in the State of Nayarit and to 

 the mountains of Alvarez in the State of San Luis Potosi. Reported 

 by Perez from Villa Lerdo, Durango. North of the Mexican bound- 

 ary, the plains toad has been recorded from a wide extent of territory. 

 It has been found in the Upper Missouri River drainage (Valley 

 County) and in southeastern Montana (Yellowstone, Rosebud, and 



Custer Counties); in north-central 

 (McHenry County) and eastern 

 (Jamestown, Stutsman County) 

 North Dakota; the Missouri Flood 

 Plain area of central South Dakota 

 (Fort Pierre); south through west- 

 ern South Dakota (Ardmore, Fall 

 River County); eastern Wyoming 

 (Laramie County) ; central Nebraska 

 (Fort Kearney) ; northeastern (Sedg- 

 wick and Weld Counties) and south- 

 central (Costilla County) Colorado; 

 western Kansas (Trego, Gove, Wal- 

 lace, and Morton Counties); north- 

 eastern New Mexico (Koehler Junc- 

 tion) ; central Oldahoma (Caddo and 

 Cleveland Counties); southwestern 

 Arkansas (Red River); the Staked 

 Plains region from the northern 

 boundary of Texas to Pecos River, 

 the salt plains of El Paso County, 

 and Jeff Davis County, Texas; central (Bernalillo County) and south- 

 western (Grant County) New Mexico; southeastern Arizona (Cochise, 

 Maricopa, and Pima Counties) and along the Colorado River at Fort 

 Mohave; Sal ton Sea Basin (Mecca and Brawley) and along the Colo- 

 rado River from Fort Yuma to Needles, Calif. ; and also in northern 

 Utah (Utah and Emery Counties). 



Remarks. — In life this toad can be recognized instantly by the 

 conspicuous greenish blotches on the upperparts. These irregular 

 spots, as will be noticed on closer inspection, vary from green to 

 brown and are margined with white or pale yellow. The parotoid 

 glands are short, broad, and widely separated; the bony crests on the 

 top of the head converge anteriorly and are united on the muzzle, 

 forming a raised boss. The so-called leopard, or plains, toad frequents 



Figure 7.— Head of Bufo cognatus (U.S.N.M. 

 No. 4626) from Nebraska: a. Lateral view; 6, 

 dorsal view 



