The types of this remarkable family of birds all belong to the 
southern hemisphere. Only the African ostrich, the original home 
of which is probably also to be looked for South of the Equator, 
lias in course of time spread into the northern hemisphere. They 
are, as it were, the pachyderms among the birds, and it is espe- 
cially upon the limited territories of the islands of the southern 
hemisphere, — which are too small to sustain large mammalia, — 
that they take their place in every respect; but they die out, where- 
cver they come in contact with man. 
But few traces of them have as yet been found in the older 
strata of the earth , which might enable us to infer the existence 
of this bird-family in the periods of the earth previous to the ap- 
pearance of man. All that can be adduced in proof of this, are 
tracks found in the New lied Sandstone of Connecticut, North 
America. If those so-called Ornithic! mites are really impressions 
made by birds, they, indeed, betoken the existence of birds of a 
colossal size, the paces of which measured five feet, and which by 
their weight pressed the mud up from the ground, as though ele- 
phants had been wading about in it. Recently Professor Owen 
has described the remains of a fossil bird (Gastornis Paris! crisis 
llebert ) from cocen strata of Paris. This excepted, whatever is 
known of giant birds, belongs to the present world, although many 
a species lias long ago succumbed in its struggle with man, and 
vanished again from the stage of actual life. 
The number of species living is very small. In all there are 
only about 12 species known; two, perhaps three species of ostrich 
in Africa, three cassuary species 1 in southern Asia, two Emu’s 
(Dromaeus) in Australia, an East and a West Australian, three spe- 
cies Rhea ; in South America, and three or four species of Kiwi 
(Apteryx) in New Zealand. Among all these the African ostrich, 
0 to 7 feet high, is known to be by far the largest and most 
numerous species. 
But greater than the number of living species is the number 
1 Among them Casuarinus Bennetti, (lie Mooruk of the natives of New Britain, 
discovered in 1858. 
