File:Image from page 62 of "Water reptiles of the past and present" (1914) (14586510237).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

View Book Page: Book Viewer About This Book: Catalog Entry View All Images: All Images From Book

Click here to view book online to see this illustration in context in a browseable online version of this book.

Text Appearing Before Image: ept the snakes; even the mammals had appeared,and possibly the birds. The Cotylosauria, Theromorpha, andTherapsida disappeared, the latter giving birth to the mammals;the nothosaurs and plesiosaurs, the ichthyosaurs, dinosaurs, croco-diles, phytosaurs, rhynchocephalians, lizards, and turtles have allleft records of their existence in Upper Triassic rocks; and thepterodactyls had also, in all probability, begun their career,though none is surely known till the Jurassic. THE AGE OF REPTILES 51 During Jurassic times all these orders of reptiles waxed pros-perous and powerful, and branched out in many ways and in count-less numbers; many new kinds of each appeared—the marinecrocodiles, the quadrupedal dinosaurs, etc.—but no order or sub-order, so far as we know, disappeared before its close. And thisprosperity continued on into the Lower Cretaceous and for manyeven into the Upper Cretaceous. The largest dinosaurs disappearedin the Lower Cretaceous, so far as our knowedge goes, but the

Text Appearing After Image: Fig. 28.—Restoration of Dimetrodon, a pelycosaur reptile from the Permian ofTexas; about eight feet long. old-fashioned crocodiles continued on into the Upper, to give placeto the new-fashioned kinds. The ichthyosaurs lingered on for awhile on the western continent, but the mosasaurs appeared, andthe plesiosaurs reached their highest evolution and continuedto the end. The flying reptiles attained the zenith of their evolu-tion, but disappeared before the close. The marine turtles attainedthe maximum of specialization and size. The upright-walkingdinosaurs continued on unabated to the close of the period; and anew kind of dinosaurs appeared near the end. 52 WATER REPTILES OF THE PAST AND PRESENT With the opening of the next great era—the Cenozoic or Tertiary—the reptiles dwindled away to their present insignificant position,while the birds and mammals appeared in great numbers andvaried forms. The Age of Reptiles was closed and the Age ofMammals had begun. The history of the rept

Note About Images