24 Merriam — Geographic Distribution of Life. 



The Boreal Re.:^ion is made \\\> of two pviucipal (livisioiis, Ijoth 

 cir('um2:)olar : (1) An Arcilr dir/.sion. a1)Ove tlie limit of tree 

 growtli ; and (2) A Borenl Coniferous Forest division. 



Arctic M(iini))(di<. 



(Found above the limit of trees and all eircnnii)olar.) 



A. Exclusively Arctic. 



Eskimo Homo 



Polar bear Tliulirrctos maritimns^ 



Barren ground bear I'rs^is richardsoni 



Musk ox Ovibos moschatus 



Barren ground caribou . Rangifer grfeulandini.t 



Arctic fox Vidpes IcKjopua 



Arctic hare Lepus glacialis 



Lemming Mi/odes ohemis 



Lemming Cunicidus torqiiatus 



Arctic red-backed mouse Eeotomy.^ rutilus 



Parry's spermophile Spennojjhilus nnpetra 



B. Common to Arctic and Hudsonian. 



Wolverine Gido luscas 



Gray wolf Canis griscus 



Ermine Putorius erminea 



The Boreal Coniferous Forest division may be subdivided into at 

 least two transcontinental zones : (a) Hudsonian, and (b) Cana- 

 dian ; and a third or ' Timberline Zone ' may l)e differentiated 

 from the Hudsonian pro])er. In sj^eaking of the divisions of the 

 Boreal Region on high mountains it is customary to add the word 

 alpine to the name of the division ; thus, Aretic-rdpine^ Hudsonian- 

 aljvne, and so on. 



3Iainmals of the Boreal Zone. 



(The letter u indicates that the species is known only from mountains, or 



is an alpine form.) 



Cervus canadensis Sciurus fremonti 



Rangifer caribou mogollonensis [a) 



Alee americanus hudsonicus 



Mazama montana t'alifornicus {a) 



Ovis canadensis vancouverensis 



dalli riclianlsoni 



Sciuropterns volans saliriims douglassi 



