. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. TEETH. 203 by no character more than by the singular seeming exception which they present to the Diphyodont rule which governs the dentition of other hoofed quadrupeds. In fact, the elephant, like the Dugong, sheds and replaces vertically only its incisors, which are also two in number, very long, and of constant growth, forming tusks, with an analogous sexual dif- erence in this respect in the female of the Asiatic species. The molars, also, are suc- cessively lost, are not vertically replaced, and are reduced finally t
. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. TEETH. 203 by no character more than by the singular seeming exception which they present to the Diphyodont rule which governs the dentition of other hoofed quadrupeds. In fact, the elephant, like the Dugong, sheds and replaces vertically only its incisors, which are also two in number, very long, and of constant growth, forming tusks, with an analogous sexual dif- erence in this respect in the female of the Asiatic species. The molars, also, are suc- cessively lost, are not vertically replaced, and are reduced finally to one on each side of both jaws, which is larger than any of its pre- decessors. These analogies are interesting and suggestive in connection with the other approximations in the " Sirenia" to the pa- chydermal type, which I have pointed out in the " Proceedings of the Zoological ; * The dentition of the genus Elephas, the sole existing modification of the once numerous and varied Proboscidian family, includes two long tusks (jig. 592.), one in each of the Intermaxillary bones, and large and complex molars (ib. in. 3, 4, and 5) in both jaws : of the latter there is never more than one wholly, or two partially, in place and use on each side at any given time; for, like the molars of the Mastodons, the series is continually in progress of formation and destruction, of shedding and replacement ; and in the ele- phants all the grinders succeed one another like true molars horizontally, from behind forwards. The total number of teeth developed in the . 2—2 6—6 elephant appears to be '-/T^Ty "''fiUfi = 28< The two large permanent tusks being pre- ceded by two small deciduous ones, and the number of molar teeth which follow one another on each side of both jaws bein^ at " The socket of the tusk in a new-born elephant, is a round cell about three lines in diameter, situated on the inner and posterior side of the aperture of the
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