GEOGRAPHICAL DISTRIBUTION 329 
species, Vireonide by 1 genus and 14 species, [cteridz by 8 genera and 
21 species, and 7'yrannidxz by 10 genera and 26 species. The first of 
these, however, cam alone be regarded as eminently characteristic of 
the area, since that affords a home to all but 3 of the genera, but 
at the same time only about half of the described species occur 
there. None of the rest can compare with it in this respect, Vir- 
eonid# having some 5 genera and 50 species, Jcteridx more than 20 
genera and more than 100 species, and Tyrannidz some 70 genera 
and over 300 species in the Neotropical Region. 
If we extend our investigation from the Families to the genera, 
we shall come to results which point the same way. It is confessedly 
difficult to make any accurate comparison owing to the tendency 
(not wholly modern) of ornithologists to propose the foundation of 
genera on very slight excuse ; but, taking the number of Nearctic 
genera at 330, which was a very liberal estimate toward the end of 
the period signalized by the labours of the late Prof. 8. F. Baird, not 
more than two dozen of them seem to be peculiar to the Nearctic 
area,! while this has about 128 genera in common with the Palearctic 
area and 178 which are also Neotropical. The genera peculiar to 
the New World, occurring both in the Nearctic area and in the 
Neotropical Region, without appearing in the Palearctic area, must 
be divided into two categories in order to obtain a just estimate of 
the relations of the first two districts. These categories. consist of 
(1) those genera which being only winter visitants to the Southern 
Region are not natives of it, and (2) those which breeding in both 
districts may fairly be called common to both. The former, some 
27 in all, must of course be considered characteristic of the Nearctic 
area, and might indeed be appropriately added to the 23 or 24 
genera which are peculiar thereto ; but if this be done, the number of 
peculiar and characteristic genera taken together reaches only 51— 
a smaller number than that of the genera of Land-birds alone (57) 
which are common to the Nearctic and Palearctic areas, and con- 
siderably less than half the number of all genera which are found 
on both, while that of the remaining genera which are common to 
the Nearctic area and the Neotropical Region is much larger again, 
being 151. Again, the total of peculiar and characteristic Nearctic 
genera being (as just said) 51, cannot compare with the 264 (or 
perhaps more) genera which are peculiar to the Neotropical Region ; 
while no one can pretend that among the former are there any 
types of such significance as the latter abundantly afford. Thus 
regarded from every ornithological aspect, what has been called 
the Nearctic “Region” has no right to be so accounted, since its 
1 Of these 2 belong to Turdidx, 1 to Chamxide, Paridx, Troglodytide 
respectively, 5 to Emberizidx, 2 to Corvidz, 1 to each of Picidw, Falconidea, 
and Columbidz, 5 to Tetraonidx, and 1 to Scolopacide, Anatide, and Laridez 
respectively, — 
