It is impossible for us to follow, or even to enumerate, all the varied ancestral lines which sprang up, some of them already vigorous, in the early Tertiary times, and which developed so mightily in the successive ages. We can only trace the careers of a few such as are better and more popularly known, while admitting that there are many others equally interesting from a scientific or from any other point of view. From a geologist's point of view the most important, perhaps, of all the mammal developments was that of the elephant. The first mammal which geologists discovered that was like the elephant was the Mastodon, the American variety of which is called _Tetrabelodon_. But this Mastodon had no proper trunk as has the elephant. Instead of that he had a very long upper lip which apparently rested on his projecting upper tusks. Mr. Kipling once suggested that the elephant's trunk was originally formed by an accident--an unfortunate young elephant before the days of trunks having stopped to drink at a pool, and his nose being seized by a crocodile, who pulled and pulled till the nose lengthened out a trunk. There certainly was some reason for the elephant's trunk, which has developed, we do not quite know how, from a long nose. But a great deal has been found out about the early development of the elephant by Dr. Andrews of the British Museum. [Illustration: Evolution of the Head, Proboscis, Nostrils, and Tusks of the Elephant The drawings are to the same scale; the nostrils indicated by the letter N, the upper lips by L, and the tusks by T. 1. Mœritherium of Eocene Libya, with a flexible upper lip and the small incisor tusks. 2. Palæomastodon of Eocene Libya, with a short proboscis and powerful upper and lower tusks. 3. Mammoth (Elephas Columbi) from the State of Indiana, with gigantic upper tusks or ivories, and long proboscis with nostrils at the tip. ]