CHAP. XVIII.] 
BIRDS. 
299 
Family 50,— ATEICHIIDJE. (1 Genus, 2 Species.) 
General Distribution. 
N EOTKOi’ICAL 
SUB-IiEQIONS. 
Neabctic 
Sub-regions, 
PALjEARCTIC 
Sub-regions. 
Ethiopian 
Sub-regions. 
Oriental 
Sub-regions. 
Australian 
Sub-regions. 
— 2 
The genus Atrichia , or Scrub-birds of Australia, have been 
formed into a separate family by Professor Newton, on account 
of peculiarities in the skeleton which separate them from all 
other Passeres. Only two species are known, inhabiting East 
and West Australia respectively. They are very noisy, brown- 
coloured birds, and have been usually classed with the 
warblers, near Amytis and other Australian species. 
General remarks on the distribution of the Passeres. 
The order Passeres, is the most extensive among birds, 
comprehending about 5,700 species grouped in 870 genera, 
and 51 families. The distribution of the genera, and of the 
families considered individually, has been already sufficiently 
given, and we now have to consider the peculiarities of dis- 
tribution of the families collectively, and in their relations to 
each other, as representing well-marked types of bird-structure. 
The first thing to be noted is, how very few of these families 
are truly cosmopolitan ; for although there are seven which 
are found in each of the great regions, yet few of these are 
widely distributed throughout all the regions, and we can 
only find three that inhabit every sub-region, and are distri- 
buted with tolerable uniformity; these are the Hirundinidse, 
or swallows, the Motacillidae or wagtails and pipits, and the 
Corvidae or crows, — but the latter is a family of so hetero- 
geneous a nature, that it possibly contains the materials of 
several natural families, and if so divided, the parts would 
probably all cease to be cosmopolitan. The Sylviidse, the 
