Page:Popular Science Monthly Volume 22.djvu/768

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THE POPULAR SCIENCE MONTHLY.

ones see the light, the mother has nourishment ready for them: part of the food which she herself eats is turned into milk, and secreted by special glands, so that the newly-born calf or kitten is suckled at its mother's breast till it has strength to feed itself.

Among the earliest milk-givers must have been the ancestors of the curious pouched creatures of Australia, the "marsupials," which have a large pouch of skin, into which the mothers put their little ones when they are less than two inches long, and so imperfect that their legs are mere knobs, and they can do nothing more than hang on to the nipple with their round, sucking mouths, as if they had grown to it.

There the little ones hang, day and night, and their mother, from time to time, pumps milk into their mouths, while they breathe by a peculiar arrangement of the windpipe, which reaches up to the back

PSM V22 D768 The pioneers of the first milk givers.jpg
Fig. 8.

of their nose. Then, as they grow, the pouch stretches, and by-and-by they begin to jump out and in, and feed on grass as well as their mother's milk.

Other singularly old-fashioned animals may be found in a Brazilian forest. The furry little opossum, the dreamy sloth, the strange ant--