Outlines of comparative physiology touching the structure and development of the races of animals, living and extinct : for the use of schools and colleges . rnal structure of the animal, theyare, at the same time, most varied inshape. Among them we find everytransition, from those of a sharp andpointed form, as in the cat tribe ( 206.—The skull of a 207), to those with broad and levelsquirrel. summits, as in the ruminants and rodents (fig. 206) ; still, when most diversified in the sameanimal, they have one character in common, their roots beingnever simple, but double or triple, a pe
Outlines of comparative physiology touching the structure and development of the races of animals, living and extinct : for the use of schools and colleges . rnal structure of the animal, theyare, at the same time, most varied inshape. Among them we find everytransition, from those of a sharp andpointed form, as in the cat tribe ( 206.—The skull of a 207), to those with broad and levelsquirrel. summits, as in the ruminants and rodents (fig. 206) ; still, when most diversified in the sameanimal, they have one character in common, their roots beingnever simple, but double or triple, a peculiarity which not onlyfixes them more firmly, but prevents them from being driveninto the jaw in the efforts of mastication. § 342. The harmony of organs, already spoken of, is illus-trated, in the most striking manner, by the study of the teethof mammals, and especially of their molar teeth. So constantlydo they correspond with the structure of other parts of thebody, that a single molar is sufficient not only to indicate themode of life of the animal to which it belongs, and to showwhether it fed on flesh or vegetables, or both, but also to de-. ORGANS OF INSALIVATION. 191 termine the particular group to which it is related ; thus, thosebeasts of prey which feed on insects, and which, on that ac-count, have been called in-sectivora, such as the molesand bats, have the molarsterminated by several sharp,conical points, so arrangedthat the elevations of onetooth fit exactly into the de-pressions of the tooth oppo-site to it. In the true car-nivora (fig. 207), on the con-
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectzoology, bookyear1870
