IT was mentioned in the last lecture that no true Proboscideans have been found below the Miocene strata, 'but among the most remarkable of the numerous recent discoveries in the Eocene formations of Wyoming Territory, North America, has been that of a group of animals of huge size, approaching, if not equalling, that of the largest existing elephants, presenting a combination of characters quite unlike those known among either recent or extinct creatures, and of which there were evidently several species living contemporaneously. To form some idea of their appearance, we must imagine animals very elephantine in their general proportions, elevated on massive pillar-like limbs, with the same complete radius and ulna, the same short, round, five-toed feet which distinguish the elephants from all other known hoofed quadrupeds. The tail, as in the elephants, was long and slender, but the neck, though still short was not so much abbreviated as in modern Proboscideans, and there is no good evidence of their having possessed a trunk. The brain was exceedingly small for the size of the creature. The head differed greatly from that of the elephants, being long and narrow, more like that of a rhinoceros, and, as in that animal, was elevated behind into a great occipital crest, but unlike that or any other known mammal, it had developed from its upper surface, three pairs of conspicuous laterally diverging protuberances, one pair from the parietal region, one over or in front of the orbits, and one near the forepart of the elongated nasal bones. Whether these were merely covered by bosses of callous skin, as the rounded form and ruggedness of their extremities would indicate, or whether they formed the bases of attachments for horns of still greater extent, either like those of the rhinoceros or the cavicorn ruminants, must still be a matter of conjecture. But in either case they must have given a very strange aspect to the creature which possessed them, and have been formidable weapons in encounters either with animals of its own kind, or with the fierce carnivorous beasts whose remains are associated in the same deposits with them. There were no incisor teeth in the upper jaw, but a pair of huge descending canine tusks very similar in position and form to those of the musk-deer. Behind these, and at some distance from them, were, on each side above and below, six molar teeth of comparatively small size, placed in continuous series, each with a pair of oblique ridges, conjoined internally, and diverging externally in a V-like manner, and with a stout basal cingulum. The lower incisors and canines were small, and are only known at present by their sockets. The dental formula is- io/3 c 1\1p 3\3 m3\3 = 34.