RUNNING BIRDS. 171 
Cursores this bone is a smooth round shield on its breast. 
While the muscles of the wings are small, those of the 
legs are very stout—their chief power is there. The plu- 
mage differs from those of birds of flight, the laminz of 
the feathers not being united together by barbs (§ 197). 
Such a union is needed for the pressure on the air re- 
quired in flying, and therefore is omitted when there is 
no flying to be done. 
280. This group of birds is, then, an aberrant one, and, 
as is usually the case in groups of this character, there 
are but few species. One of the most pronfinent is the 
African Ostrich. This is the tallest of all birds, reach- 
ing sometimes even to eight feet. It is found in the 
sandy deserts of Africa and Arabia. It is probably the 
swiftest of all running animals. It can be domesticated, 
and will easily carry two men on its back. Its nest is 
merely a hollow made in the sand, and the hatching of 
the eggs is not left to the heat of the sun, but both the 
male and female bird engage in the incubation. The 
Bushmen make of these shells water-flasks, cups, and dish- 
es. The food of the Ostrich consists of the tops of shrub- 
by plants, seeds, and grain. It swallows, also, stones, 
sticks, bits of metal, leather, etc., probably guided by in- 
stinct, as these will help the grinding of the food, as the 
gravel does which the common Fowl swallows. There 
is an American Ostrich, a smaller bird, found in the south- 
ern part of South America. 
281. The Emu, Fig. 138 (page 172), a native of Austra- 
lia, is nearly as large as the Ostrich, but is lower on the 
legs, has a shorter neck, and is more thickset in body.. 
The wings are mere rudiments, and are concealed be- 
neath the feathers of the body. The feathers strongly 
resemble branching hairs, the laminz being at a distance 
from each other. The Cassowary, a native of Java and 
the neighboring islands, is much smaller than the Os- 
trich. Of all the Cursores, the Apteryx of New Zealand 
is the one most completely destitute of wings. It has a 
