216 BIRDS

There are two species of ostrich, both of them
African. The ostrich is the largest existing bird—
sometimes he may be eight feet high; but the New
Zealand moas, extinct but recently, exceeded ten feet
in height, and the eggs of another of the group—the
Madagascar zepyornis—held six times as much as
those of the ostrich, though the height of the mature
birds need not necessarily have been in the same
ratio.

Of the rheas there are three species, all South
American, and all, like the ostriches, wonderfully good
runners. The ostrich roars like a lion ; the rhea is
said to sing, for it-alone among the Ratte has a
syrinx in its throat, like the carinates.. Of the casso-
waries there are eight species, distributed over New
Guinea, the north of Australia, Ceram, and the islands
to the eastward. They are recognisable at once by
their horny helmets and the spines on their wings,
as well as by the long claw on the inner toe,
with which they fight. The emus have claws of
nearly equal length on all three toes, They are,
however, more easily distinguished from the casso-
waries by the absence of the neck wattles and of the
horny helmet. There are two species of emu,
Dromeus, both Australian, both very shy and speedy,
and both with hardly any wing to speak of. Lowest
of all of this group we have the kiwi, the Apteryx
(that is, the wingless one), a New Zealander, about a
couple of feet high, with an enormous egg for his
size. There are four species, the biggest being A.
maximus, all of them nocturnal, feeding chiefly on
the earthworm, drawing it forth with its long bill