File:The American Museum journal (c1900-(1918)) (17972860878).jpg

Title: The American Museum journal
Identifier: americanmuseumjo13amer (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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344 THE AMERICAN MUSEUM JOURNAL Attention may be called to the relatively enormous size of the skull and the curious way in which the long point of the lower jaw passes up into the groove in the upper. We find many other mammal-like reptiles of which the Therocephalians, Dromasaurians, and the Cynodonts are the most important. Although these insectivorous and carnivorous types are less mammal-like in some respects than the Anomodonts, they agree more closely with the mammals in the construction of the skull. They all have long, slender limbs adapted for running. The earlier members such as the lower Therocephalians, have the number of toe joints as still found in the lizards and most reptiles, viz.— 2, 3, 4, 5, 3; but the Anomodonts, the lower Dromasaurians and the higher Cynodonts have the same number of joints in the toes as is retained in our- selves viz.— 2, 3, 3, 3, 3. It is rather interesting to look at one's hand and
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Inostrancevia alexandri Amalitsky. A photograph of a skeleton of one of the large mam- mal-like reptiles found fossil on the banks of the Dvina River in north Russia. The skeleton is of large size, the skull being about two feet in length and is extremely closely allied and perhaps identical with some forms found in South Africa realize that the fingers have all these joints because a remote ancestor took to walking with the feet under the body supporting it off the ground rather than with the feet to the side as in the lizards and crocodiles. The Cynodonts occur in the Triassic formation and a few survive into the Jurassic. In most points of structure they are extremely mammal-like and it is frequently impossible if the specimen is at all incomplete to say whether we are dealing with one of the Cynodonts or a mammal. The lower jaw is almost entirely formed by a large single bone, the posterior bones being small, and the bone on which the jaw hinges is also small thus foreshadowing the mammalian condition, the dentary bone, the angular, articular and sur- angular being quite small, as is also the quadrate bone. The teeth are in most forms of a carnivorous type, composed of sharp incisors, long sharp

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