e
that the mammal must of necessity give to her young operated in the
direction of affording a special protection far superior to that of the
other forms. This and other causes acted to place the Placentals in the
"Royal line" from which Man was evolved.

The following families of Placental Mammals are recognized by Science,
each having its own structural peculiarities:

The _Edentata_, or Toothless creatures, among which are the sloths,
ant-eaters, armadillos, etc. These animals seem to be closer to the
Monotremes than they are to the Marsupials;

The _Sirenia_, so called by reason of their fanciful resemblance to the
sirens of mythology, among which are the sea-cows, manatees, dugongs,
etc., which are fish-like in structure and appearance, the fore-limbs
being shaped like paddles, or fins, and the hind-limbs being absent or
rudimentary;

The _Cetacea_, or Whale Family, including whales, Porpoises, dolphins,
etc., which are quite fish-like in appearance and structure, their
forms being adapted for life in the sea, although they are, of course,
Mammals, bringing forth matured young which are suckled at the breast;

The _Ungulata_, or Hoofed Animals, which comprise many varied forms,
such as the horse, the tapir, the rhinoceros, the swine, the
hippopotamus, the camel, the deer, the sheep, the cow, etc., etc.;

The _Hyracoidea_, which is a small family, the principal member of
which is the coney, or rock rabbit, which has teeth resembling those of
the hoofed animals, in some ways, and those of the gnawing animals in
the others.

The _Proboscidea_, or Trunked Animals, which family is represented in
this age only by the families of elephants, which have a peculiar
appendage called a "trunk," which they use as an additional limb;

The _Carnivora_, or Flesh-eaters, represented by numerous and various
forms, such as the seal, the bear, the weasel, the wolf, the dog, the
lion, the tiger, the leopard, etc. The wolf and similar forms belong to
the sub-family of dogs; while the lion, tiger, etc., belong to the
sub-family of cats;

The _Rodentia_, or Gnawers, comprising the rat, the hare, the beaver,
the squirrel, the mouse, etc., etc.;

The _Insectivora_, or Insect Feeders, comprising the mole, the shrew,
the hedgehog, etc.;

The _Chiroptera_, or Finger-Winged Animals, comprising the great family
of Bats, etc., which are very highly developed animals;

The _Lemuroidea_, or Lemurs, the name of which is derived from t