DENTATE

(Lat. dens.) In Zoology, the margin of a part of an animal is so termed when it is cut into teeth whose S'des are equal, or nearly so. DENTATUS (Lat. dens.) Toothed; applied lo the margins of bodies furnished with sharp teeth with concave edges. DENTES (Lat. the teeth), properly so called, are parts peculiar to the vertebrate animals, composed of gelatin, hardened principally by the phosphate of lime, and are fixed to Ihe bones of the mouth. They serve to catch, kill, hold, pierce, cut, or crush the objects of food, and are variously shaped accordingly. Substances composed of softer material, generally horn, perform the analogous cilices in Ihe invertebrate animals, and are generally called teeth; horny material is substituted for teeth in n few fishes, In clielonians. birds, whales, and the Omithorhynchns paradox us. In fishes the teeth may be siluated ort the Intermaxillary, maxillary, mandibular, palatine, vomerine, pterygoid, hyoid, or pharyngeal hones; in a few instances they are implanted in sockets or "alveoli," or they may he fixed to an o eous base which is attached by ligamentous substance to the oral bones; but most commonly ihey are immediately anchylosed, or joined by a direct continuation of bony substance, to the bones themselves which encompa the mouth. In reptiles the teelh may be. found on the palatine, pterygoid,or vomerine, as well as on the maxillary and inlermaxillary bones. They are generally anchylosed, or confluent with the substance of the jaws; but in the plesiosaurs and crocodiles are implanted in sockets. In mammals the teeth are confined to the maxillary and intermaxillary bones, are always implanted in sockets, and in this cla only may be so fixed by more than one fang or root. Teeth generally consist of three distinct substances; viz. ivory, enamel, and bone, or caementum, also called crusla petrosa.The texture of the ivory is minutely tubular, that of the caementum of combined tubules and cells; and the earthy material is arranged principally in these cavities, which have definite arrangement and proportions in each species of animal. The enamel consists of hexagonal filamentary crystals. In the human suhject the teeth are called, according to their figure, "incisors," "canines," "bicuspids* and "molars;" Ihe same terms have been transferred to the teeth of Ihe mammal i a generally, except that those which are analogous to the bicuspids in man are called "premolars,"or spurious molars. A tooth is divided into i crown, a neck, and a fang or fangs. The vascular bodies concerned in their development are called "pulp" and "capsule:" the ivory or body of the tooth is formed by the former the enamel and cement ara due to the latter organ. [s. 342]