. College collection of palaeontology. MAMMALIA. 9 taiuing the transverse processes. The cervical vertebrae are thin and sometimes united in living species. The true Dolphin lias forty-seven sharp, conical, crooked teeth in each ramus, and are well represented in the Miocene. The order is confined to the Tertiary and Recent Periods. The most numerous fossil relics (teeth and ear-bones) have been found in the Red Crag, England, but evidently washed out of Eocene strata. The Balcenidm appear in the Pliocene. No. 12. [177] Zeuglodon hydrarchlis, Skull (cast). This carnivorous whale typifi
. College collection of palaeontology. MAMMALIA. 9 taiuing the transverse processes. The cervical vertebrae are thin and sometimes united in living species. The true Dolphin lias forty-seven sharp, conical, crooked teeth in each ramus, and are well represented in the Miocene. The order is confined to the Tertiary and Recent Periods. The most numerous fossil relics (teeth and ear-bones) have been found in the Red Crag, England, but evidently washed out of Eocene strata. The Balcenidm appear in the Pliocene. No. 12. [177] Zeuglodon hydrarchlis, Skull (cast). This carnivorous whale typifies a distinct family, the only one having teeth implanted by two roots. Its teeth were first described by Scilla in 1747; in 1836 by Harlan under the name of Basilosmiriis and Squalo- don ; and in 1839 by Owen, who first determined the mammalian and cetacean nature of the animal. When full grown, it was probably seventy feet in length. The slvuU is long and narrow; the nostril single and looking upward. It was discovered in a marl deposit of the "Jackson epoch" (Middle Eocene) in Claiborne, Alabama, and belongs to theTylerian Museum at Haarlem. Size, 35 X 13. No. 13. [176] Zeuglodon cetoides, Owen. Two Teeth (cast). The jaws of the Zevylodon are armed with teeth of two kinds, set wide apart; the anterior have subcompressed, conical, slightly recurved, sharp, pointed crowns, and are implanted by a single root; the posterior are larger, with more compressed and longitudinally extended crowns, and witli botli front and liind borders deeply notched or serrated. The crown is contracted from side to side in the middle of its base, so as to give its transverse section an hour-glass form. The root of the pos terior teeth has two fangs. The mode of succession conforms to the general mammalian type more than any existing carnivorous Cetacean: i. e. the decidu ous tooth is displaced and succeeded vertically by a second molar. Tliese fossil teeth, one anterior, the other posterio
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