514 Characteristics of the Central Zoé-Geographical [ August, © 
sion of it. It, however, lacks the-mammalian genera Bos and 
Antilocapra, and possesses certain mae genera of birds, as 
Geococcyx, Chameaand Oreortyx. ... There are some genera 
of reptiles, ¢. g. Charina, related to “the Boas, Lodia, Aniella, 
Gerrhonotus and Xantusia, which do not occur in the central sub- 
region. There are three characteristic genera of Batrachia, all 
Salamanders, viz: Anaides, Batrachoseps and Dicamptodon ; while 
the eastern genera Plethodon and Diemyctylus reappear after 
skipping the entire central district.” Cope adds that “ the fresh- 
water fish fauna is much like that of the central district in being 
poor in types.” Cope’s Sonoran region is evidently a northward 
extension of the Mexican fauna, which sends its outliers into 
southern Arizona, Utah and New Mexico, and is not to be taken 
into account in discussing the faunal provinces of the United 
States alone. 
In 1876, Wallace in his “Geographical Distribution of Ani- 
mals,” divided the Nearctic region into four sub-regions, viz: 
the Californian, Central or Rocky mountain, Alleghanian and 
Canadian. His Central sub-region extended to Lat. 25° N. 
It will be seen from this review that by general consent the 
fauna of the Pacific slope is on the whole regarded as belonging 
to a separate province from that of the Rocky Mountain plateau, 
` whether we regard the mammals, birds, reptiles, amphilia, Cole- 
optera or land shells. 
Botanically, as observed by those who have traveled across the 
plains to California, the flora of the great plains is quite different | 
from that of the Eastern States, and the Pacific flora is as distinct 
from the central flora. This has been clearly shown by Sir J. D. 
Hooker and Prof. Asa Gray in their preliminary notices of the 
results of their botanical researches in connection with Dr. Hay- 
den’s U. S. Geological Survey of the Territories. 
In traveling last summer, in pursuance of the work of the US 
Entomological Commission, I passed rapidly over a large area of 
the Central province lying north of the fortieth parallel, including 
Colorado, Wyoming, Northern Utah, Western Idaho, Central and 
Northern Montana, and was thus enabled to observein a superficial 
-way the general features of the flora and fauna nearly up to the 
- British line. I was impressed with the resemblance of Central 
and Northern Montana to Northern Utah, the insect-fauna being 
E TOS AE COSY 
apparently nearly identical. Doubtless this. insect-fauna extends 
