. Animal activities : a first book in zoölogy. Zoology; Animal behavior. MAN'S hi EAR RELATIVES {MAMMALS). 231 and a harder substance called enamel. In a human tooth the enamel covers entirely the outside of that part of the tooth known as the crown. The root, or fang, of the tooth is covered by a substance called cement. The greater part of the tooth is dentine. In the teeth of many animals which must grind their food for a long time the enamel and dentine are so folded together that hard sharp ridges of enamel are produced above valleys. When these valleys are deep they are filled with cemen
. Animal activities : a first book in zoölogy. Zoology; Animal behavior. MAN'S hi EAR RELATIVES {MAMMALS). 231 and a harder substance called enamel. In a human tooth the enamel covers entirely the outside of that part of the tooth known as the crown. The root, or fang, of the tooth is covered by a substance called cement. The greater part of the tooth is dentine. In the teeth of many animals which must grind their food for a long time the enamel and dentine are so folded together that hard sharp ridges of enamel are produced above valleys. When these valleys are deep they are filled with cement, as in the case of the molar teeth of. Fig. 194.—Skull of Cow Showing the Bone of the Horn. the horse. As these teeth wear away the dentine and cement wear faster than the enamel and the ridges become more prominent. Gnawing animals, like the squirrel, have teeth fitted with enamel in front and dentine behind. As the teeth are used the dentine is worn away and a sharp chisel of enamel is produced. These teeth constantly increase in length from below, and, if they are not worn away fast enough, they sometimes grow so long that they cannot be used at all and the animal starves. In every. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original French, Nathaniel S. (Nathaniel Stowers), 1854-. New York ; London : Longmans, Green, and Co.
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Keywords: ., bookcentury1900, bookdecade1900, booksubjecta, booksubjectzoology
