THE UNIVERSITY OF CHICAGO PRESS 



the aquatic habitats of a much larger territory. Six chapters 

 deal with general principles. 



In several chapters animal communities of lakes, streams, 

 swamps, forests, prairies, and various soils and topographic 

 situations are considered from the point of view of modern 

 dynamic ecology. A very valuable feature of the book is the 

 three hundred figures of widely distributed animals chosen to 

 represent the chief types of animal communities and their 

 characteristic modes of life. 



Bulletin of the American Geographical Society. This book is unique in that 



it is a pioneer of its sort and the first serious attempt to treat of the 

 physiology of organisms and of animal communities in such shape as 

 to serve as an adequate .text and reference work for students. 



Water Reptiles of the Past and Present. By Samuel Wendell 



Williston, Professor of Paleontology in the University < 

 Chicago. 



viii-f 252 pages, royal 8vo, cloth; $3.00, postage extra (weight 2 lbs. 8 oz.) 



Professor Williston, who is widely known as a student of ex- 

 tinct reptiles and as the author of American Permian Vertebrates, 

 which has now become a recognized authority, presents in this 

 new volume a summary, divested as far as possible of unneces- 

 sary scientific details, of our present knowledge concerning the 

 reptiles of the seas, lakes, and rivers of past and present times. 

 While no attempt has been made, save incidentally, to discuss 

 the strictly terrestrial reptiles, twelve of the fourteen orders of 

 the class recognized by the author are treated more or less fully 

 their structure, habits, geological distribution, etc. Unlike 

 most of the works for the general reader treating of "ancient 

 monsters," the present work is by an author who has spent many 

 years in the field and laboratory in the collection and study of 

 extinct reptiles, upon which he has an international reputation 

 as an authority. 



The numerous illustrations, in large part from the pen or 

 brush of the author himself, include not only living types and 

 twenty-four restorations of extinct forms, but also many figures 

 elucidating the structure and habits of the animals. 



