THE AMERICAN FAUNA AND ITS ORIGIN. 
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Nearctic families not 
Families common to 
Palsearetic families not 
in Paliearctic Region. 
both Regions. 
Chelonia. 
Testudinidae. 
in Nearctic Region. 
1 
Trionychidae. 
Cheloniidae. 
Amphibia. 
Urodela. 
Sirenidse. 
Proteidae. 
Amphiumidse. 
Menopomidae. 
Salamandridae. 
Anoura. 
Engystonidag. 
Bufonidae. 
Bombinatoridae. 
Alytidae. 
Hylidae. 
Polypedatidae. 
Eanidae. 
Discoglossidae. 
From this tabular statement it will be found that there are 
twenty families of mammalia, forty of birds, and twenty of 
reptilia and amphibia, or no less than eighty families of 
vertebrates common to the Nearctic and Palmare tic regions, 
and that while there are forty-eight Paliearctic families not 
represented in the Nearctic region, there are only twenty-three 
Nearctic families not in the Paliearctic region. 
It also appears that seven families of the order Carnivora 
are common to both regions, while only one, Procyonidae, is 
confined to the Nearctic. Of birds fourteen families of the 
order Passeres are represented in both regions, and five of 
Picariae, while of Accipitres, birds of prey, all four families 
are in both regions. Of Grail ae seven families are common 
and not one peculiar to the Nearctic region. The order 
Anseres, or swimming birds, has, like Accipitres, all of its 
families, seven, represented in both regions. 
These facts compel the conclusion that the northern parts 
of the Old and New Worlds have been connected by land and 
that the animals of North America have, for the most pare at 
least, been derived from migrants from the Palaearctic region. 
