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 col- 

 lector, 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. 



Those broken and incomplete specimens, now preserved in the 

 museum of Yale University, will best explain why this little book 

 was written. The author offers it, so far as lies within him, as an 

 authoritative and accurate account of some of the creatures of 

 earlier ages which sought new opportunities by going down from 

 the land into the water. So far as possible he has endeavored to 

 make the text understandable, and, he hopes, of interest also, to the 

 non-scientific reader. He will not apologize for such scientific 

 terms as remain, since only by their use can precision be attained: 

 there are no common English equivalents for them. The reader 

 will And their explanations in the chapter on the skeleton of reptiles, 

 and especially in the illustrations. 



The author has had the opportunity during recent years of 

 critically studying nearly all the reptiles described in the following 

 pages, but, if that were the only source of his information, the 

 accounts of many would have been meager. He has endeavored, 

 briefly at least, to mention the names of all those to whom we are 

 chiefly indebted for our knowledge, but in such a work as this it is 

 manifestly impracticable to give due credit to every one. 



