File:The American Museum journal (c1900-(1918)) (17971586368).jpg

Title: The American Museum journal
Identifier: americanmuseumjo05amer (find matches)
Year: c1900-(1918) (c190s)
Authors: American Museum of Natural History
Subjects: Natural history
Publisher: New York : American Museum of Natural History
Contributing Library: American Museum of Natural History Library
Digitizing Sponsor: Biodiversity Heritage Library

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24 THE AMERICAN MUSEUM JOURNAL fall into one or another of the living families and are more or less directly ancestral to the modern beasts of prey. The re- mainder belong to several extinct branches, not ancestral to any of the modern families, and are combined in the rather hetero- geneous group of Creodonta. Seals and Walruses have not been found fossil, except in the most recent deposits, and nothing is known of their evolution. A. CREODONTA, OR PRIMITIVE CARNIVORA. In all modern Carnivora one tooth in the upper and one in the lower jaw are enlarged and especially adapted to the cutting of flesh. Each consists mainly of a high strong crest, or ridge.
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FIG. 2. UPPER AND LOWER TEETH OF THE WOLF Shows the carnassials or fiesk-cutting teeth (the fourth premolar in the upper jaw, the first true molar in the lower) and the two crests, or "blades," work against each other like the blades of a pair of scissors. These teeth are called the "car- nassials," or flesh-teeth. In all the modern Carnivora the fourth (last) upper premolar and the first lower true molar are the c&r- nassial teeth. The fossil species show the gradual evolution of this specialized tooth in the various families of Carnivores. In the Creodonta, on the other hand, there is either no camassial tooth, or it is developed from other teeth of the series,—in one group the first upper and second lower true molars, in another the second upper and third lower molars. (Compare Figures 2, 3, 4 and 5.)

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