. Biology of the vertebrates : a comparative study of man and his animal allies. Vertebrates; Vertebrates -- Anatomy; Anatomy, Comparative. Intake Apparatus 287 point to the phrase "as clean as a hound's tooth," and it also serves as a currycomb for fur-bearers, while animals like cats and dogs that lap up liquids use it as a spoon. Finally, its dorsal surface is thickly beset with sense organs of touch and taste, which stand in readiness to receive the password of admittance from entering food. In the human female it measures about three and a half inches in length—when at rest. 6.
. Biology of the vertebrates : a comparative study of man and his animal allies. Vertebrates; Vertebrates -- Anatomy; Anatomy, Comparative. Intake Apparatus 287 point to the phrase "as clean as a hound's tooth," and it also serves as a currycomb for fur-bearers, while animals like cats and dogs that lap up liquids use it as a spoon. Finally, its dorsal surface is thickly beset with sense organs of touch and taste, which stand in readiness to receive the password of admittance from entering food. In the human female it measures about three and a half inches in length—when at rest. 6. Teeth Teeth are primarily devoted to the manipulation of food within the mouth cavity, to purposes of grasping, cutting or grinding, although in some instances they secondarily assume other functions, such as prehension of food, defence, offence, or even as aids in locomotion, as in the case of the walrus which uses its tusks in dragging its slippery body out of arctic water on to ice (Fig. 60). The extreme diversity of teeth, adapted to their many uses, affords the comparative anatomist much insight into the manner of life of different animals, while to the palaeontologist they are preserved tokens which, like hiero- glyphics, aid in reconstructing the story of the long-vanished past. Teeth are the first hard structures of the body to put in an appearance during vertebrate development, even before any part of the bony skeleton. Although they eventually come into intimate secondary relation with the skeleton, they are in real- ity derivatives of the stomodaeal region of the alimentary tract. Thus these integu- mentary derivatives, homologous with pla- coid scales, become morphologically, as well as physiologically, a part of the diges- tive system. (a) Structure.— In structure a typical mammalian tooth (Fig. 240) consists of a crown which projects beyond the gums; roots that are embedded in a socket of the jaw; and the neck, which is the transitional region between the crow
Size: 1279px × 1953px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, booksubjectanatomycomparative, booksubjectverte
