III.—On the Milk Dentition of Palæotherium Magnum

Extract

In the British Museum there is the right ramus of the mandible of a young Palœotherium magnum, obtained by M. Bravard from the Eocene strata of Vaucluse, which possesses a peculiar interest, inasmuch as the three principal milk molars are completely cut, though their unworn crowns show that they have not long been, in place. The ramus itself must have been nearly eight inches long when it was complete, while the distance from the articular surface of the condyle to the lower margin is about 3·25in. The symphysial surface is oval, rugose, and extends back nearly as far as the anterior margin of the crown of the first visible grinder; the anterior, or mental region of the ramus, is inclined upwards and forwards, and is slightly convex, as in all the true Palœotheria. In front of the most anterior milk molar which is in place, there is an oval fossa about 0·2in. long, which appears to lead into the alveolus of the proper first milk molar (dm¹); and further forward (but not more than 0·2in., so that the diastema of the milk teeth must have been exceedingly short) a series of depressions on the truncated anterior end of the ramus represent the bottoms of the alveoli of the canine and incisors.