. The comparative anatomy of the domesticated animals. Horses; Veterinary anatomy. THE F(ETU8. 1049 The enamel is derived from the deep cells of its gertn, which are elongated and prism-shaped, cUid are calcitied on becoming applied to the surface of the ivory. Tlie cemenium is developed at the expense of the walls of the follicle, accord- ing to the mode of ossification of the connective tissue. Eruption.âAs the ivory is formed, the tooth increases in length and presses the enamel germ upwards ; tiie latter, constantly compressed, becomes atrophied, and finally disappears when the tooth has r
. The comparative anatomy of the domesticated animals. Horses; Veterinary anatomy. THE F(ETU8. 1049 The enamel is derived from the deep cells of its gertn, which are elongated and prism-shaped, cUid are calcitied on becoming applied to the surface of the ivory. Tlie cemenium is developed at the expense of the walls of the follicle, accord- ing to the mode of ossification of the connective tissue. Eruption.âAs the ivory is formed, the tooth increases in length and presses the enamel germ upwards ; tiie latter, constantly compressed, becomes atrophied, and finally disappears when the tooth has reached the summit of the follicle. In the same way the young organ pierces the dental follicle and gum, and makes its eruption externally. Such is the mode of development of the deciduous teeth. The permanent ones are formed in the same manner. The enamel organ proceeds from a point adjoining the summit of the follicle of the temporary tooth, and buries itself beneath the latter, where it forms the dental bulb and the walls of the new follicle. The follicles of the three last molarsâwiiich are permanentâarise independently of those of the temporary teeth. The bud of the first of these molars springs from the epithelial ridge on the border of the jaws, the buds of the other two being derived from the first. 3. The liver.âThis gland commences to be developed very early in all the species. It appears on the surface of the duodenum in the form of two or more buds, according to the number of lobules in the adult liver. To these external buds are conesponding intenial ones, arising from the intestinal epitheliumâ that is, the inner lamina of the blastoderm. The first are contained in a layer of the mesoblast that separates the anterior aditus of the pericardium ; they grow and ^'g- ^^^- envelop the omphalo-mesenteric vein ; the second ramify in their interior, and form the system of biliary canals. The liver grows rapidly, and, towards the third month, almost entirely fills the
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Keywords: ., bookauthorcha, bookcentury1900, bookdecade1900, booksubjecthorses
