. Elements of comparative zoology. Zoology. MAMMALS. 367. FIG. 158.—Milk (shaded) and perma- nent dentitions (outline) of the cat. c, canines; p—p4, premolars; m, molar. The incisors (to left) not lettered. From Boas. have teeth. These teeth are always confined to the edges of the jaws (c/. Fishes, p. 24), being in- serted by one or more roots into sockets in the bone. Some mammals have but a W single set of teeth through- out life, but the majority have a first or milk dentition, which is soon lost and re- placed by a permanent den- tition. Occasionally, as in the sperm-whale, etc., all the t
. Elements of comparative zoology. Zoology. MAMMALS. 367. FIG. 158.—Milk (shaded) and perma- nent dentitions (outline) of the cat. c, canines; p—p4, premolars; m, molar. The incisors (to left) not lettered. From Boas. have teeth. These teeth are always confined to the edges of the jaws (c/. Fishes, p. 24), being in- serted by one or more roots into sockets in the bone. Some mammals have but a W single set of teeth through- out life, but the majority have a first or milk dentition, which is soon lost and re- placed by a permanent den- tition. Occasionally, as in the sperm-whale, etc., all the teeth are similar in shape, but usually several different kinds occur, the extreme being reached when four types are present—incisors, canines, premolars, and molars. The incisors have but a single root, and are found in the premaxillary bone and in the corresponding position in the lower jaw. The first teeth in the maxillary, if single- rooted and pointed, are called canines; and behind these come the molars, with two or more roots. These in turn are subdivided into premolars (the bicuspids of the dentist), which appear in both milk and permanent dentitions, and molars proper, which occur only in the permanent set. The number of teeth and their arrangement vary con- siderably in different mammals, and the characters which they furnish are of great value in grouping the various species. To express these characteristics briefly a dental formula has been introduced, in which the different kinds of teeth are indicated by initials, while the number in \j each half of either jaw is represented by a figure above or below a horizontal line. Thus the permanent dentition of. 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 Kingsley, J. S. (John Sterling), 1854-1929. New York, H. Holt and Company
Size: 1548px × 1613px
Photo credit: © Paul Fearn / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, booksubjectzoology, bookyear1904
