“ 
GEOGRAPHICAL DISTRIBUTION 323 
MORPHA. Both the Dromxognathe and Heteromorphxe are indubit- 
ably of low developmental rank; in that respect, though in no 
other, resembling certain Australian and New-Zealand groups ; but 
the similarity between the Avifaunas of the three Regions composing 
his Wotogxa seems to be further borne out by the same fact being 
observable in other South-American Families forming the lower 
sections or suborders of Passeres, to which the names of OLIGo- 
MYyop%and TRACHEOPHONA have been applied—the Neotropical 
Region having a complete monopoly of the latter and a large pro- 
portion of the former,’ according to our present knowledge. Of 
the species of Passeres, belonging to the Region, we find that a little 
more than one-half have to be classed under the highest sections of 
that Order, while nearly one-half must be ranked under its two lowest 
sections.” This is a state of things that exists nowhere else, and it 
is believed that much the same result would appear from a close 
scrutiny of other Orders, especially of the Picarivx. But more than 
this, if we examine the true Passeres we find similar indications. 
Their highest group, the Corvidx, is only just represented in the 
northern portion by its highest genus Corvus, and even its lower forms, 
belonging to the subfamily Garruline (JAY), only occur in parts of the 
rest: the Fringillide though inhabiting the Region are vastly out- 
numbered by the Tanagridx, and the Mniotiltide occupy the position 
elsewhere taken by the Sylviide. 
Leaving, however, this question as in some degree hypothetical, 
though its probability can hardly be denied, we have as genera, 
Families, or even larger groups, a great many remarkable forms 
that are characteristic of or peculiar to the Neotropical Region in 
part if not asa whole. Of Families there are more than a score 
absolutely restricted to it, beside some half-dozen which, being 
peculiar to the New World, extend their range into the Nearctic 
area, but are there so feebly developed that wherever they may 
have originated in bygone ages, they may be safely ascribed now 
to South America. First in point of numbers come the Zvochilidx 
(HUMMING-BIRD) with, according to some systematists, nearly 150 
genera, of which perhaps only 3 occur in the Nearctic area. 
Then the 7yrannidx (KING-BIRD) with above 70 genera, yet scarcely 
more than 10 ranging into the Holarctic Region. To these follow 
the Tanagride (TANAGER) with 40 genera, only 1 of which crosses 
the border ; and, in addition to those before mentioned the various 
Families of Conopophagide, Cotingidx, Dendrocolaptidx, Formicaride, 
Furnaviide (OVEN-BIRD), Pipridw (MANAKIN), and Pleroptochide 
1 The exceptions are Tyrannidx, which occur in comparatively small pro- 
portion in North America, Pittide, Philepittide, Acanthidosittidz, and Euryle- 
mide. 
2 The section which for want of a better name we have to call ‘‘ Psewdoscines” 
has hitherto been found peculiar to Australia, 
