Transcriber’s Notes: Underscores “_” before and after a word or phrase indicate _italics_ in the original text. Equal signs “=” before and after a word or phrase indicate =bold= in the original text. Small capitals have been converted to SOLID capitals. Illustrations have been moved so they do not break up paragraphs. Typographical and punctuation errors have been silently corrected. THE UNIVERSITY OF CHICAGO PRESS CHICAGO, ILLINOIS _Agents_ THE CAMBRIDGE UNIVERSITY PRESS LONDON AND EDINBURGH THE MARUZEN-KABUSHIKI-KAISHA TOKYO, OSAKA, KYOTO KARL W. HIERSEMANN LEIPZIG THE BAKER & TAYLOR COMPANY NEW YORK WATER REPTILES OF THE PAST AND PRESENT BY SAMUEL WENDELL WILLISTON _Professor of Paleontology in the University of Chicago_ [Illustration] THE UNIVERSITY OF CHICAGO PRESS CHICAGO, ILLINOIS COPYRIGHT 1914 BY THE UNIVERSITY OF CHICAGO All Rights Reserved Published October 1914 Composed and Printed By The University of Chicago Press Chicago, Illinois, U.S.A. PREFACE It was just forty years ago that the writer of these lines, then an assistant of his beloved teacher, the late Professor B. F. Mudge, dug from the chalk rocks of the Great Plains his first specimens of water reptiles, mosasaurs and plesiosaurs. To the youthful collector, whose first glimpse of ancient vertebrate life had been the result of accident, these specimens opened up a new world and diverted the course of his life. They were rudely collected, after the way of those times, for modern methods were impracticable with the rifle in one hand and the pick in the other. Nor was much known in those days of these or other ancient creatures, for the science of vertebrate paleontology was yet very young. There were few students of fossil vertebrates—Leidy, Cope, and Marsh were the only ones in the United States—and but few collectors, of whom the writer alone survives.