GEOGRAPHICAL DISTRIBUTION 331 



Reaching the eastern frontier of Canada, it rapidly inclines west- 

 ward and loses itself in the Arctic wilds. But this Province melts 

 away also on its north-eastern border, and cannot there be sharply 

 distinguished from what may be named the " Canadian," which 

 occupies the north-eastern portion of the continent, including the 

 eastern half of the Dominion, and it must be held to extend across 

 Davis Strait to Greenland, though it only fringes the shore of that 

 ice-bound country, while here and there on the continent it follows 

 the higher ranges southward, even to Fort Burgwyn near lat. 

 37° N. if not further. Then on the west we have a " Calif ornian " 

 Province, the longitudinal extent of which is very indefinite. 

 Prof. Heilprin would cut off the southern portion, annexing it to 

 the Neotropical Region, and its eastern boundary would seem to 

 proceed along the Sierra Nevada and the Cascade Mountains, so 

 that it is restricted to a mere strip of coast territory, extending, 

 however, beyond British Columbia. Between this Californian and 

 the Alleghanian Province is interposed a considerable tract of 

 country called by many American writers the " Middle Province," 

 a name so vague that it would seem allowable to distinguish it as 

 the " Missourian " since its characteristic vertebrates culminate 

 (so to speak) in the wide basin of that greatest of tributaries to 

 the Mississippi.^ Occupying the extreme north-west of the con- 

 tinent, a fifth Province, the "Alaskan," must be recognized, and 

 this from a zoogeographical point of view is the most important 

 of all, since it is characterized by the presence of Mammals and 

 Land-birds, which are not only specifically identical with those of 

 Asia, but among them some individually have an Asiatic resort. 

 The list of Birds observed in this Province, which may be taken as 

 beginning about Cape St. Elias, and thence extending northward to 

 the Icy Sea, seems (after such revision as can at present be made) 

 to number 227,^ of which 112, or very nearly one-half, are also 

 Asiatic. Dividing the whole into Water-birds and Land-birds, we 

 find that of the former (127) more than 66 and of the latter (100) 

 exactly 27 per cent, are found on both sides of the Pacific. More- 

 over no fewer than 11 of the 100 species of Land-birds, belonging 



^ Indication of its being the focus (if snch a thing can now exist) of purely 

 Nearctic types is not wanting, since here we find at least one generalized or 

 undifferentiated genus, Colaptes (Flicker), which both to the north and to the 

 south separates itself into specific forms. 



- The gross number given in 1887 by Messrs. Nelson and Henshaw in their 

 Report upon Natural History Collections made in Alaska (pp. 19-226) is 255, but 28 

 of these should be deducted as not being known to occur to the northward of Cape 

 St. Elias or the Alaska Mountains, where apparently a very natural frontier exists. 

 This Report contains a useful bibliography of Alaskan ornithology. In making 

 the estimates given in the text above, all the subspecies or conspecies recognized 

 by the authors have been treated as true species. Were it otherwise the results 

 would .still more favour the views here expressed. 



