136 
ZOOLOGICAL GEOGRAPHY. 
[PART III. 
celebrated for its power of ejecting a terribly offensive liquid, the 
odour of which is almost intolerable. The skunks are nocturnal 
animals, and are generally marked, as in the species represented, 
with conspicuous bands and patches of white. This enables 
them to be easily seen at night, and thus serves to warn larger 
animals not to attack them. To the left is the curious little 
jumping mouse (Baculus hudsonius), the American representative 
of the Palsearctic jerboa. Climbing up a tree on the left is the 
tree porcupine (. Erethizon doi'satus ), belonging to the family Cer- 
eolabidae, which represents, on the American continent, the por- 
cupines of the Old World. In the background is the elk or 
moose (Alces americanus), perhaps identical with the European 
elk, and the most striking inhabitant of the northern forests of 
America, as the bison is of the prairies. 
Birds. — Although the Canadian sub-region possesses very few 
resident birds, the numbers wdiich breed in it are perhaps greater 
than in the other sub-regions, because a large number of circum- 
polar species are found here exclusively. Erom a comparison of 
Mr. Allen’s tables it appears, that more than 200 species are 
regular migrants to Canada in the breeding season, and nearly 
half of these are land-birds. Among them are to be found a 
considerable number of genera of the American families Tyran- 
nidse and Mniotiltidse, as well as the American genera Sialia h 
Brogue, Vireo, Cistothorus, Bunco, Pipit o, Zonotrichia, Spizella, 
Melospizci, Mohihrus , Agelceus, Cyanura, Sphyrcipicus, and many 
others ; so that the ornithology of these northern regions is still 
mainly Nearctic in character. Besides these, it has such specially 
northern forms as Surnia (Strigidse) ; Bicoides (Picidse) ; Pinicola 
(Fringillidse) ; as well as leucosticte , Pledrophanes, Berisoreus, 
and Lagopus , which extend further south, especially in the middle 
sub-region. No less than 212 species of birds have been col- 
lected in the new United States territory of Alaska (formerly 
Prussian America), where a humming-bird (Sdasphorus rufus) 
breeds. The great majority of these are typically American, 
including such forms as Colaptes , Helminthophaga , Siurus , Den- 
drceca , Myiodioctes , Basser cuius , Zonotrichia , Bunco , Spizella t 
Melospizpa, Passerella, Scoleophagas , Bediocetes , and Bonasa ; 
