imultaneously, as
may be seen in the complete skull shown in Fig. 14. Of other teeth it
had only the two moderate-sized front tusks above and two very big,
chisel-like "incisors" in the front of the lower jaw. Exactly how
these were used and for what food no one has yet made out.

[Illustration: Fig. 13.--Head of the ancestral elephant--Palaeomastodon--as
it appeared in life. It shows, as compared with the earlier ancestor,
an elongation both of the snout and the lower jaws. The tusk in the
upper jaw has increased in size, but is still small as compared with
that of later elephants. (After a drawing by Prof. Osborne.)]

[Illustration: Fig. 14.--Restored model of the skull and lower jaw of
the ancestral elephant Palaeomastodon from the upper Eocene strata of
the Fayoum Desert, Egypt. It shows the six molar teeth of the upper
and lower jaw (left side), the tusk-like upper incisors and the large
chisel-like lower incisors in front.]

The remains, which finally bring the elephants into line with the
ordinary mammals with typical dentition, were discovered also by Dr.
Andrews and named "Meritherium" by him, signifying "the beast of the
Lake Meris." This creature is not bigger than a tapir, and had the
shape of head and face which we see in that and the ordinary hoofed
animals (Fig. 15). It had no trunk, and whilst it had six small and
simplified mastodon-like grinders in each half of each jaw, it had six
incisors in the upper jaw and a canine or corner tooth on each side.
In the lower jaw there were only two large incisors besides the
cheek-teeth or grinders. Not the least interesting point about
Meritherium is that it tells us which of the front upper teeth have
become the huge tusks of the later elephants. Counting from the middle
line there are in Meritherium three incisors right and three left. The
second of these upper teeth on each side is much larger than the
others. It is this (seen in Fig. 15) which has grown larger and larger
in later descendants of this primitive form and become the elephant's
tusk, whilst all the others have disappeared.

[Illustration: Fig. 15.--Head of the early ancestor of
elephants--Meritherium--as it appeared in life. Observe the absence of
a trunk and the enlarged front tooth in the upper jaw, which is
converted in later members of the elephant-stock or line of descent
into the great tusk. (After a drawing by Prof. Osborne.)]

We now know the complete series of steps connecting elephan