Distribution 



carolinense, Scaphiopus couchii, Bufo debilis, Bufo pundatus, Bufo 

 compactilis, and Bufo valliceps. 



The country between this western section of Texas and the 

 Western plains north of it, on the one hand, and the Sierras on the 

 other, presents little besides barren mountains, desert valleys, and 

 areas of sagebrush. It possesses two species of toads and one 

 spadefoot; namely, Bufo I. woodbousei, Bufo cognatus, and Scaphi- 

 opus bammondii. However, this part of the Sonoran subregion 

 is penetrated even as far as Arizona and New Mexico by the less 

 dry Transition zones, and so this part of North America has a 

 few other species of toads and frogs; these are Rana onca, Rana 

 pipiens, and Bufo boreas nelsoni. The last is the southern moun- 

 tain subspecies of Bufo boreas which is found at the north - - both 

 east and west of the Sierras. Rana pipiens, abundant in eastern 

 North America, in Texas, and on the Western plains, reaches its 

 western limit just east of the Sierras. 



At the south, in Arizona and New Mexico, in addition to 

 Bufo cognatus, Bufol. woodbousei, and Rana pipiens, are found Bufo 

 balopbilus, Bufo alvarius, Bufo punctatus, and Hyla arenicolor, 

 the latter two entering from Mexico. 



The peninsula of Lower California has no species of Salientia 

 peculiar to it. It reports Rana draytonii, Hyla regilla, Bufo punc- 

 tatus, Bufo balopbilus, and Scaphiopus couchii. 



The narrow stretch of country between the Pacific and the 

 Sierra Nevada, made up of California, Oregon, and Washington 

 is arid in its southern portion (Sonoran) 1 , humid and forested 

 at the north (Transition). At the south are found Bufo balo- 

 pbilus, Hyla regilla, Rana draytonii, and, rarely, Rana boylii. The 

 north has a longer list; namely, Bufo boreas, Bufo balophilus colum- 

 biensis, Hyla regilla, Scaphiopus hammondii, Rana draytonii, Rana 

 boylii, Rana pretiosa, and Rana aurora. These are, for the most 

 part, species not found elsewhere in North America. Some of them 

 follow the temporary streams of the rainy season into the desert 

 regions of California and Nevada on the eastern slope of the 

 Sierras. Hyla regilla, for instance, is often found in springs from 

 fifteen to forty miles distant from other water, having been 

 stranded there during flood times of previous years, when the 

 springs were temporarily in connection with streams. 



1 Named Diegan division by Dr. John Van Denbergh, San Francisco. 



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