. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. RUMINANTIA. 533 gle example -will illustrate the points most deserving of attention. The true mohir tooth of the permanent series has a quadrilateral form, its outer and inner lateral surfaces being bounded by mar- gins more or less convoluted. The crown in the young state presents four elevated cusps, which, by subsequent attrition, disappear. The ground surface, thus flattened, is marked in the centre by double crescent-shaped ridges of enamel, so disposed as to present, along with the central mass of dentine and exter
. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. RUMINANTIA. 533 gle example -will illustrate the points most deserving of attention. The true mohir tooth of the permanent series has a quadrilateral form, its outer and inner lateral surfaces being bounded by mar- gins more or less convoluted. The crown in the young state presents four elevated cusps, which, by subsequent attrition, disappear. The ground surface, thus flattened, is marked in the centre by double crescent-shaped ridges of enamel, so disposed as to present, along with the central mass of dentine and external crust of ccmetitum, alternate layers of hardened tissue, having different degrees of density. By such an arrangement it conse- quently follows that the enamel being the least affected by trituration, remains some- what above the level of the other dental sub- stances,—a condition highly favourable for the due performance of mastication, and one re- sulting in all cases from the vertical folding of the original formative capsule. The upper molars of certain individuals present an ac- cessory island-shaped portion of enamel at the internal border, by which the extent of grinding surface becomes enlarged. This additional facet only makes its appearance in a tooth which has been employed for some time, as it depends upon the wearing down of a columnar fold which is developed at the side between the lobes, and which does not extend so high up as the summit of the crown in the unworn tooth ; it is well seen in the Ox and Deer (p, fig. 356.) Fig. Molar ton tli of the Deer. (From Owen's " ;) Tongue. — The lingual organ undergoes certain modifications, in accordance with the habits and kind of aliment on which the ru- minant subsists. These peculiarities do not involve any material departure from the type of structure invariably found in other mam- mifers ; on the contrary, the muscular ele- ments and their relations to surrounding parts remain nea
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