File:Image from page 185 of "Water reptiles of the past and present" (1914) (14772723072).jpg

Identifier: waterreptilesofp1914will Title: Water reptiles of the past and present Year: 1914 (1910s) Authors: Williston, Samuel Wendell, 1851-1918 Subjects: Aquatic reptiles Publisher: Chicago, Ill., The University of Chicago Press Contributing Library: Boston Public Library Digitizing Sponsor: Boston Public Library

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Text Appearing Before Image: Fig. 83.—Dorsal ver-tebra of Thalattosaurus.(After Merriam.) J74 WATER REPTILES OF THE PAST AND PRESENT

Text Appearing After Image: like those of the mosasaurs, as will be seen by comparing the figureon p. 157. The humerus is a little more elongated than that ofthe mosasaurs, more nearly like the mosasaurian femur. Theshoulder-blade and the coracoid are imperfectly ossified, as is seenfrom the figure—another characteristic of aquatic life. What thefingers and toes were like cannot be said; probably they were bound together by membrane, formingswimming paddles similar to those of themosasaurs. Some of the bones referred to the pelvis are known, but it is not knownwhether they are united to the spinalcolumn by a sacrum, as in land animals.Nor is anything certainly known of thehind leg or much of the tail. Since thefront legs show marked aquatic adapta-tions, it is altogether certain that the hindlegs will be found to be modified more orless, though not so much modified as thefront legs, because, as we have seen, thefront legs are always more specialized inaquatic animals than the hind ones, evenas the hind legs are

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