CHAt. xv.] THE NEARCTIC REGION. 135 



americanus), and the ground dove (Chamcepelia passerina). The 

 most regular visitants are a kingfisher (Ceryle alcyon), the wood- 

 wagtail (Siurus noveboracensis), the rice-bird (Dolichonyx oryzivo- 

 rus), and a moorhen (Gallinula galeata). Besides the American 

 species, four European birds have been taken at the Bermudas : 

 Saxicola oenanthe, Alauda arvensis (perhaps introduced), Crex 

 pratensis, and Scolopax gallinago. 



A common American lizard, Plestiodon longirostris, is the only 

 land reptile found on the islands. 



IV. The Sub- Arctic or Canadian Sub-region. 



This sub-region serves to connect together the oth£r three, 

 since they all merge gradually into it; while to the north it 

 passes into the circumpolar zone which is common to the Palse- 

 arctic and Nearctic regions. The greater portion of it is an exten- 

 sive forest-district, mostly of coniferse ; and where these cease 

 towards the north, barren wastes extend to the polar ocean. It 

 possesses several northern or arctic forms of Mammalia, such as 

 the glutton, lemming, reindeer, and elk, which barely enter the 

 more southern sub-regions ; as well as the polar bear and arctic 

 fox ; but it also has some peculiar forms, and many of the most 

 characteristic Nearctic types. The remarkable musk-sheep 

 (Ovibos) is confined to this sub-region, ranging over a con- 

 siderable extent of country north of the forests, as well as 

 Greenland. It has been extinct in Europe and Asia since the 

 Post-pliocene epoch. Such purely Nearctic genera as> Procyon, 

 Latax, Erethizon, Jacidus, Fiber, Thomomys, and Hesperomys, 

 abound, many of them ranging to the shores of Hudson's Bay 

 and the barren wastes of northern Labrador. Others, such as 

 Blarina, Condylura, and Mephitis, are found only in Nova Scotia 

 and various parts of Canada. About 20 species of Mammalia 

 seem to be peculiar to this sub-region. 



Plate XX. Illustrating the Zoology of Canada. — We have 

 here a group of Mammalia characteristic of Canada and the 

 colder parts of the United States. Conspicuous in the fore- 

 ground is the skunk {Mephitis mephitiea), belonging to a genus 

 of the weasel family found only in America. Tnis animal is 



Vol. XL— 10 



