The marsupial mammals were followed by the placental mammals, animals
whose young are nourished before birth by a disc-like organ, called the
placenta—the after-birth.
The Pariasaurus Baini (Fig. 21) shows Nature, the apprentice, trying to
make a quadruped. I say trying, for see what a crude, raw specimen this
monster was. The best thing that can be said of this fellow is that he
had his day of fighting for a place in the sun and was then supplanted
by higher creatures.
Many ages of progress, during which life assumed a rich variety of
forms, including the early stages of most of the hoofed animals,
brought the process of evolution to the lemurs, the monkey-like
creatures that make their home in trees (Fig. 22). The lemurs differ
from monkeys in that the milk glands of the female are on the abdomen
instead of the breast, while the index finger of each hand, and the
second toe of each foot, are furnished with claws, all the other
fingers and toes having flat nails. Here again is a link between the
lower and the higher life. Nature is stumbling and bungling, but
getting there.
[Illustration: FIG. 19.—THE DUCK-BILL, KNOWN IN AUSTRALIA AS THE
PLATYPUS.]
After the lemurs came the Slow Loris (Fig. 23). This species of the
Loris has no tail, and its front foot bears a strong resemblance
to the human hand. From these creatures, or possibly from similar
creatures, were evolved the true apes (Fig. 24), and from these came
the anthropoid or man-like apes.
There are still in existence four genera, or kinds, of these anthropoid
apes—the gibbon, the gorilla, the orang, and the chimpanzee. The gibbon
(Fig. 25) shows an alert, human-like expression, which is fully borne
out in his pose. The picture of a female gorilla (Fig. 26) suggests
with even greater force that we have here a human being in the making.
Yet this creature, be it understood, may be separated from the lowest
living human being by millions of years of development. The giant
gorilla (Fig. 27), shot by Paschen, in the Cameroons, differed from
the ordinary gorilla in the development of the skull and in size.
He was six feet, eight inches tall from the crown of his head to
his middle toe; the span of his arms was six feet, nine inches; his
chest measurement was twice as great as that of a strong man. Yes, a
dangerous gentleman to meet!
[Illustration: FIG. 20.—A KANGAROO WITH HER YOUNG ONE IN HER POUCH.
The illustration to the right shows a young Kangaroo shortly after
birth. That the creature is a quite unfinished fœtus is obvious.]
The approach to the human look on the face of the bald-headed
chimpanzee (Fig. 28) is nothing less than remarkable. The form of the
skull shows a decided advance towards the human. The countenance is, of
course, a little open, but—well, the whole head so strongly resembles
the human that he might almost be mistaken for one who believes the
story of Jonah and the whale!
That man is related to the anthropoid apes becomes evident when his
anatomical structure is compared with theirs (Fig. 29). While these
creatures differ from one another as do the different races of men, as,
for example, in the color of the skin, in the size and shape of the
skull, and in the length of the arms and legs, they are all essentially
man-like. And while all these creatures are like human beings in the
formation of their skeletons, in their anatomical structure, and in
their physiological functioning, each of them approaches more closely
to man than any of the others in the development of some part of its
body. Thus, “the orang approaches closest to man in the formation of
the brain, the chimpanzee in the shape of the spine and in certain
characteristics of the skull, the gorilla in the development of the
feet and in size, and the gibbon in the formation of the throat and
teeth.” Prof. Ernst Haeckel, in the “Riddle of the Universe,” sums up
man’s relation to the anthropoids as follows:
[Illustration: FIG. 21.—THE PARIASAURUS BAINI.