. A manual of zoology. Zoology. 644 CHORD AT Fig. 667.—Inside of left lower jaw of Klephai^ indicium, the alveoli opened. (After Owen.) i, functional molar; 2. its successor. at a time is functional (fig. 607, long proboscis with a finger-like process at the tip, lastly by the dentition. Canines are entirely lacking, but the incisors of the ujiper jaw have pnlps and therefore continue to grow throughout life, forming the well-known tusks. In the living elephants there are but a single pair of tusks, but in some extinct JIastodons there were a second smaller pair in the lower jaw, while in
. A manual of zoology. Zoology. 644 CHORD AT Fig. 667.—Inside of left lower jaw of Klephai^ indicium, the alveoli opened. (After Owen.) i, functional molar; 2. its successor. at a time is functional (fig. 607, long proboscis with a finger-like process at the tip, lastly by the dentition. Canines are entirely lacking, but the incisors of the ujiper jaw have pnlps and therefore continue to grow throughout life, forming the well-known tusks. In the living elephants there are but a single pair of tusks, but in some extinct JIastodons there were a second smaller pair in the lower jaw, while in Dinotlieriiuii only the lower in- cisors were developed, these pro- jecting downwards. The molars (in Mastodon and Dinotherium with normal replacement and cusps) consist of numerous plates of enamel and dentine united by cement, and undergo a lateral displacement. Of the three large molars and premolars only one 1); when worn out the next one behind (5) takes its place. Further features are a uterus bicornis, a zonary placenta, and two j^ectoral mamma3. : Eleplias indicus, small ears ; i?. afrieanus, large ears. ^. primegenius, mammoth, in the pleistocene ; specimens found frozen in ice in Siberia have close woolly hair, in some places three feet long. Mastodon, with tuberculate teeth, range from miocene through the pliocene. DiNOTHEElDiE, only lower incisors ; DiiiotJierium, Old "iTorld miocene. Order VII. Hyracoidea. The single genus H>/ra:r, including species from western Asia and Afrida, with four-toed front feet, hind feet with three toes, tlie digits with nails, the placenta zonary, and the dentition i-jjf, forms this group, no fossils being known. Hi/rax syriacus is sup- posed to be the ' coney' of the Bible. Order VIII. Sirenia. This order consists of a few aquatic mammals which are whale- like in form, with the fore limbs fin-like, the hind legs lacking, and a horizontal caudal fin. They live in shallow seas or in the mouths of rivers, where they
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