ds a distinctly better chance in life. The
protection of the bitter mucous and the large amount of yolk
permitting considerably larger development before leaving the egg,
give to the toad a material advantage. When the toad first emerges
from the egg it is amazingly like the fish. It has gills at the side
of its neck and swims by the movement of its tail. Later its limbs
develop, the hind ones coming first, its tail is absorbed, and it is
now a true toad, ready to leave the water.

Altogether a higher state of reproduction is encountered when we reach
the reptiles, which are the next higher class of backboned animals.
Here very distinct developments of the process are discovered. The
turtle, to use the best known illustration, may lay but twenty eggs.
But she will not lay them at random in the water, as do the toads and
the fish. Each egg is wonderfully fattened with yolk. This means that
it is possible for the creature to develop to a far greater extent
before leaving the egg than was possible in the case of the toad.
Accordingly the little turtle, while it begins life not unlike a fish
and goes through the gilled and tailed period, during which it is not
unlike a tadpole, passes beyond this period before leaving the shell
and has already acquired its full turtle characters when first it
steps upon the scene. So big an egg as this would be highly nutritious
and animals would desire it immensely for food. Hence it becomes
necessary for the turtle to securely hide her eggs. In order to do
this, she scoops out a pit in the sand in which she deposits them and
here they develop. If no further provisions were made the eggs of the
turtle would dry completely and never hatch. Accordingly it becomes
necessary for the turtle to enclose each egg in a tough, leathery
membrane, known as the shell. Because the egg is thus encased it is
necessary for it to be fertilized before being laid. Accordingly the
male must place the sperm cells within the body of the female. These
cells swim nearly to the top of the tubes in which they are placed,
and there fertilize the descending eggs. Farther down the canal the
shell is secreted about the now swollen mass of yolk and white,
completing the egg just before it leaves the parent.

If the evolutionist understands properly the line of descent, the
birds and mammals are both the descendants of the reptiles. While
there is less exterior resemblance between a chicken and a turtle than
between a c