The Sclerotic Ring in the Hadrosauridae (Classic Reprint)

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Excerpt from The Sclerotic Ring in the HadrosauridaeSclerotic ossifications or chondrifications are known in a great variety of vertebrates, exclusive of mammals and modern amphibians (edinger, Those of birds have been most systematically studied, not ably by Lemmrich This author established the fact that the sclerotic ring in birds consists of 11 to 16 plates, which are scale-like, and more or less overlapping. The overlap is not continuous in one di rcction, there is one plate, or more, which overlaps at both ends (plus-plate), and one, or more, which is doubly overlapped (minus-plate). 'where only one of each of these plates is present the ring is divided into two halves, more or less anterior and posterior, respectively, and not usually symmetrical. The minus plate lies near the top and the plus-plate near the bottom. In the second case, where two plus and minus plates are present, the ring becomes divided into four quadrants, with the plus~plates above and below, and the minus - plates in front and in rear. Lemmrich desig nated these two types of arrangement as B and.a, re spectively. The accompanying copies of his diagrams (fig.l) make the distinction clear.About the PublisherForgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.comThis book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully, any imperfections that remain are intentionally left to preserve the state of such historical works.