410 GEOGRAPHIC DISTRIBUTION OF LIFE IN NORTH AMERICA. 
North America (the Nearctic region of Selater and Wallace) consists of 
but two primary life regions; a boreal region, which is circumpolar, 
and a Sonoran or Mexican table-land region, which is unique.” The 
so-called eastern province is mainly of Sonoran derivation, comprising 
the humid divisions of the Lower Sonoran and Upper Sonoran zones 
(Austro-riparian and Carolinian faunas), and of the transition or neutral 
belt, commonly known among ornithologists as the Alleghanian fauna. 
It contains also a southward extension of the boreal region along the 
Appalachian mountain system, mainly in the form of isolated islands. 
The so-called central region in like manner is made up of a southward 
extension of the boreal region along the Rocky mountain plateau, inclosed 
between two northward prolongations of the arid Sonoran, the one 
occupying the Great plains, the other the Great basin. 
The so-called Pacific or western province consists of a southward 
extension of the boreal region, which finally bifurcates, sending a long 
arm south over the Cascade range and the Sierra Nevada, and a sec- 
ondary and shorter arm along the Pacific coast, north of San Francisco, 
together with a Sonoran element, which covers nearly the whole south- 
ern part of the state, and reaches north in the San Joaquin and Sacra- 
mento valleys. 
PALAHARCTIC AND NEARCTIC REGIONS. 
It is no part of the purpose of the present address to discuss the 
distribution of life outside of our own continent, but it so happens 
that the Boreal element in America resembles that of Eurasia so closely 
that in the judgment of many eminent authorities the two constitute 
but a single primary region, a view in which I heartily concur. This 
arrangement is antagonistic to that proposed by Sclater* in 1857, and 
adopted with slight modification by Wallace. Sclater considers the 
whole of extra-tropical North America as constituting a single region, 
upon which he bestowed the name Nearctic, in contra-distinction to the 
corresponding part of Eurasia, which he named Palearctic, believing 
the two to be distinct primary regions. 
Wallace, the great champion of Sclater’s Palearctic and Nearctic 
regions, says of the former in his most recent work on geographic dis- 
tribution: “Taking first the mammalia, we find this region is distin- 
guished by its possession of the entire family of Talpide or Moles, con- 
sisting of 8 genera and 16 species, all of which are confined to it, except 
one, which is found in northwest America, and two which extend to 
Assam and Formosa.” (Island Life, 1880, 41.) How he could have 
made such an erroneous statement is hard to understand, in view of 
the well known fact that 3 genera of moles inhabit eastern North 
America and 2 the Pacific coast region; and it is the more strange 
* Journ. Linn. Soc. (Zod1.) (for 1857), 1858, 1m, 130-145; and again, with some altera- 
tions, in Ibis, 1891, sixth series, 111, 514-557. 
_——.  "* 
