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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1902 Excerpt:...other varieties, such as depressed, hemispherical, or even pavement-like; some have bevelled edges, or are chisel-or spade-shaped, and a few are multicuspidate. Pleodont teeth have solid crowns, as contrasted with coelodont, which grow from persistent pulps. Thecodont or socketed teeth are inserted in alveoli, acrodout fused with the supporting bone along the outer rim or top, and pleurodont teeth are developed laterally along the flange-like inner rim of the jaw. With the exception of Snakes and certain Lacertilians, two pairs of limbs are always present. In the pectoral arch the principal bones are the coracoid and scapula, the former usually exceeding the latter in size, and forming either alone or in connection with the scapula the glenoid cavity for the humerus. Clavicular and interclavicular elements may or may not be present, and the same is true of the precoracoid, which occurs usually as an anteriorly directed process of the coracoid. The scapulae are normally directed upward and backward, and are well separated by the clavicular arch when present. The interclavicle (or episternum), may be rhomboidal, cruciform, or T-shaped, and differs from the adjacent bones in being of membranous origin. Posterior to the interclavicle is usually a flat, rhomboidal, or aspidate sternum, to which the anterior dorsal ribs are attached by means of intermediate pieces. Very frequently the sternum is wanting; when present its anterolateral margin is always applied against the coracoid, and when absent the coracoids unite in a median symphysis or are joined together by ligaments. The appendicular skeleton is constituted essentially as in Amphibians. In the fore-limb the humerus of some fossil forms is pierced at its distal end by one or two foramina, as in certain mamm...