CREATION BY EVOLUTION
of the lower jaw and to manipulate the food dug up with the lower incisors. Palaeomastodon was about four and a half feet high and seems to have improved or specialized in the habit of digging roots and fleshy vegetables. In these same Oligocene beds of Egypt we find still another and more progressive form, Phiomia, which may well be called the “long-jawed mastodon,” for the lower jaw is still longer and the neck is still shorter.
At the beginning of Miocene time there was in Europe a group of long-jawed mastodons closely related to Phiomia. They migrated from Africa to Europe and increased in size until they were about eight feet high. The lower jaw was as much as six feet long. After reaching Europe these long-jawed Mastodons spread over the continent and migrated to Asia and finally to North America across land that then connected the continents. In Pliocene time this form culminated in Trilophodon giganteus, which was almost as large as the later mammoths. In most animals the neck elongates as they increase in size, so that the mouth can be brought to the ground for feeding or drinking, but in Trilophodon the neck steadily shortened, and the necessity of reaching the ground has been met by elongating the jaws. The two large shovel-like teeth of the lower jaws indicate that these large forms were still digging roots and fleshy bulbs for food. The upper jaw is not so long, but the two upper tusks are long enough nearly to touch the ground and probably aided the lower tusks in digging and pushing aside the earth. The upper lip must have been correspondingly long.
This is a critical time in the history of the elephants. The dinotheres, mastodons, mammoths, and elephants of later time all seem to have gone through this long-jawed stage. In the Miocene epoch some of the long-jawed mastodons changed from the habit of digging to that of browsing on
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