. On the anatomy of vertebrates [electronic resource] . the molar teeth,in the advance of the part of its own alveolus, which contains itshollow root. The upper jaw of a Rabbit, with an analogous ab-normal growth of the scalpriform and accessory incisors, is shownin fig. 239. d. Insectivora.—The dental system in this order is remarkablefor the many varieties and even anomalies which it presents—almost the only characteristic predicable of it being the presenceof sharp points or cusps upon the crowns of the molar teeth,which are always broader in the upper than in the lower teeth that i
. On the anatomy of vertebrates [electronic resource] . the molar teeth,in the advance of the part of its own alveolus, which contains itshollow root. The upper jaw of a Rabbit, with an analogous ab-normal growth of the scalpriform and accessory incisors, is shownin fig. 239. d. Insectivora.—The dental system in this order is remarkablefor the many varieties and even anomalies which it presents—almost the only characteristic predicable of it being the presenceof sharp points or cusps upon the crowns of the molar teeth,which are always broader in the upper than in the lower teeth that intervene between these and the incisors are mostvariable in form and size, but are never absent; the incisorsdiffer in number, size, and shape, in different species, the anteriorones approximating in some species to the character of the scalpri-form teeth of the Rodents. They may be wholly absent in theupper jaw, fig. 242, A. The Chrysochlore, or iridescent Mole of the Cape, makes thenearest approach, by the number of its molar teeth, fig. 240, to. 302 ANATOMY OF VERTEBRATES. that remarkable condition which a solitary genus (Myrmecobius)of existing Marsupials also presents, and which was more abun-240 dantly manifested in the 4- 2 extinct Amphitheria and rz n r- A —^ Spalacotheria of the Oo-litic period. At least f iftrue molars may be as-signed to the Chryso-chlore according to theirform—the only charac-ter, in the absence of theknown order of theirvertical displacement andsuccession, by which thetrue and false molars canat present be defined inthis species. In theupper jaw, ib. 1, the an-terior large laniariformtooth, and the two suc-ceeding small teeth, are 1. Upper jaw, & side view, a grinding surface. incisOrS, by virtue of 2. Lower jaw, a grinding surface, 6 side view. , ... , their position in the pre-maxillary bones; the next small tooth, with a simple compressedtricuspid crown, may be regarded either as a canine or a crowns of the true molars are t
Size: 1814px × 1377px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, booksubject, booksubjectbirds, booksubjectfishes
