Guide to the gallery of Reptilia and Amphibia : in the Department of zoology of the British museum (Natural history) / Illustrated by 76 text and other figures.

  • British Museum (Natural History). Department of Zoology.
Date:
1906
Catalogue details

Licence: In copyright

Credit: Guide to the gallery of Reptilia and Amphibia : in the Department of zoology of the British museum (Natural history) / Illustrated by 76 text and other figures. Source: Wellcome Collection.

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    to the margins of the jaws, the two-headed ribs, the absence of a perforation in the lower end of the humerus, and the adaptation of the limbs for walking. They differ in that the ischia, or anterior elements of the lower part of the pelvis, unite in the middle line of the abdomen, and by the circumstance that when the vertebrae articulate by cup-and-ball joints, the cup (except occasionally in the tail) is behind (opistho- ccelous). No Dinosaurs have the pitted bony plates found in most Crocodiles. The group is divided into four sub-orders :— I. Sauropoda.—Includes gigantic herbivorous, plantigrade Rep- tiles, walking on all four limbs, with teeth in the front of both jaws, the pubes of the pelvis simple and meeting in the middle line of the abdomen, and the trunk-vertebrae with lateral cavities. The teeth are spatulate, with smooth edges. Some of the species, like Brontosaurus, were about sixty feet in length and ten in height. Generally, as in Cardiodon {Cetiosaurus) and Diplodocus (41), the skull is small. II. Theropoda.—The members of this group differ from the Sauropoda by their digitigrade feet, carnivorous habits, laterally-compressed and serrated teeth, and the absence of excavations in the trunk-vertebrae. Many of them, like Megalosaurus (39) and the diminutive Gompsognathus, assumed the erect posture. III. Ornithopoda.—The division of the pubis into apre-pubic and a post-pubic branch, neither of which meets in the middle line of the abdomen, forms a distinctive feature of this group, in which the front of both jaws is devoid of teeth, while the lower jaw is provided with a distinct premandibular bone. Teeth complicated, seldom in separate sockets. All the forms are herbivorous. In one section (Stegosauria) the feet are plantigrade, with more than three toes, the limb- bones are solid, and bony plates and spines protect the body. Scelidosaurus (42), Stegosaurus, and Hylceosaurus are well- known genera. In a second section (Iguanodontia) the hind-feet are digitigrade, with three functional toes, the limb- bones hollow, and the body unarmoured. The group includes Iguanodon (43), Gamptosaurus, Trachodon, etc., all bipedal. IV. Ceratopsia.—Includes gigantic quadrupedal Reptiles, with a bony neck-shield, a premandibular and a prerostral bone, a