. On the anatomy of vertebrates [electronic resource] . tition, lower jaw, of Ilycenodon. 340 ANATOMY OF VERTEBRATES. feeding animal, allied to the viverrine and canine families, thetrue molars presenting the tuberculate modification, and thetypical number and kinds of teeth being functionally developed,as in the Hycenodon. The series in the upper jaw are shown infig. 267. The term £ tubercular is as applicable to the threetrue molars of the Amphicyon, m 1, 2, 3, as the term ( carnassialis to those of the Hycenodon. 267. Dentition, upper jaw, Amphicyon. § 221. Teeth of Ungulata.— The most comm
. On the anatomy of vertebrates [electronic resource] . tition, lower jaw, of Ilycenodon. 340 ANATOMY OF VERTEBRATES. feeding animal, allied to the viverrine and canine families, thetrue molars presenting the tuberculate modification, and thetypical number and kinds of teeth being functionally developed,as in the Hycenodon. The series in the upper jaw are shown infig. 267. The term £ tubercular is as applicable to the threetrue molars of the Amphicyon, m 1, 2, 3, as the term ( carnassialis to those of the Hycenodon. 267. Dentition, upper jaw, Amphicyon. § 221. Teeth of Ungulata.— The most common characteristic ofthis dentition is the large size, cuboid shape, and complex structureof the crowns of the grinding teeth. The enamel not only inclosesbut dips or penetrates into the substance of the dentinal body,and the cement, which is thick, accompanies the enamel. Thusthe massive grinding organ is made up of substances of differentdensities, and the working surface is irregular by the projectionsof the harder material, as in the mineral 6 grit that is therebysuitable as a millstone. A. Homologies of the parts of the grinding surface.—The patternof the grinding surface, especially of the upper molars, varies ineach genus of Ungulata, and is eminently characteristic , two leading types may be recognised. One, of un-symmetrical character, was early shown in Palceotherium, and istraceable in secondary modifications characteristic of Paloplothe-riumf Hipparion, Equus, Hyrax, and Rhinoc
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