cetoides_ of Owen, which attained a length of seventy feet. Remains of these gigantic Whales are very common in the "Jackson Beds" of the Southern United States. So common are they that, according to Dana, "the large vertebræ, some of them a foot and a half long and a foot in diameter, were formerly so abundant over the country, in Alabama, that they were used for making walls, or were burned to rid the fields of them." [Illustration: Fig. 228.--_Zeuglodon cetoides_. A, Molar tooth of the natural size; B, Vertebra, reduced in size. From the Middle Eocene of the United States. (After Lyell.)] The great and important order of the Hoofed Quadrupeds (_Ungulata_) is represented in the Eocene by examples of both of its two principal sections--namely, those with an uneven number of toes (one or three) on the foot (_Perissodactyle Ungulates_), and those with an even number of toes (two or four) to each foot (_Artiodactyle Ungulates_). Amongst the Odd-toed Ungulates, the living family of the Tapirs (_Tapirdoe_) is represented by the genus _Coryphodon_ of Owen. Nearly related to the preceding are the species of _Paloeotherium_, which have a historical interest as being amongst the first of the Tertiary Mammals investigated by the illustrious Cuvier. Several species of _Paloeothere_ are known, varying greatly in size, the smallest being little bigger than a hare, whilst the largest must have equalled a good-sized horse in its dimensions. The species of _Paloeotherium_ appear to have agreed with the existing Tapirs in possessing a lengthened and flexible nose, which formed a short proboscis or trunk (fig. 229), suitable as an instrument for stripping off the foliage of trees--the characters of the molar teeth showing them to have been strictly herbivorous in their habits. They differ, however, from the Tapirs, amongst other characters, in the fact that both the fore and the hind feet possessed three toes each; whereas in the latter there are four toes on each fore-foot, and the hind-feet alone are three-toed. The remains of _Paloeotheria_ have been found in such abundance in certain localities as to show that these animals roamed in great herds over the fertile plains of France and the south of England during the later portion of the Eocene period. The accompanying illustration (fig. 229) represents the notion which the great Cuvier was induced by his researches to form as to the outward appearance of _Paloeotherium magnum_. Recent discoveries, however, have rendered it probable that this restoration is in some important respects inaccurate. Instead of being bulky, massive, and more or less resembling the living Tapirs in form, it would rather appear that _Paloeotherium magnum_ was in reality a slender, graceful, and long-necked animal, more closely resembling in general figure a Llama, or certain of the Antelopes. [Illustration: Fig. 229.--Outline of _Paloeotherium magnum_, restored. Upper Eocene, Europe. (After Cuvier.)]