vi WATER REPTILES OF THE PAST AND PRESENT 



To the friends who have been of assistance in various ways he 

 tenders his sincere thanks: to Professor E. Fraas for photographs 

 • and the kind permission to reproduce some of his excellent illus- 

 trations; to Dr. Dreverman, of the Senckenberg Museum, for 

 several excellent photographs for reproduction or restoration; to 

 Dr. Hauff, of Holzmaden, for an excellent photograph of an 

 ichthyosaur; to Dr. H. F. Osborn, of the American Museum, for 

 permission to reproduce the spirited restoration of ichthyosaurs 

 drawn by Mr. Knight; to Professors Schuchert and Lull, and 

 Dr. Wieland, of Yale University; to Dr. Hay and Mr. Gilmore, of 

 the National Museum, to Mr. Barnum Brown and Dr. McGregor, 

 of the American Museum, and to Professor Merriam, of the 

 University of California, for photographs and other favors. 



Samuel W. Williston 



University of Chicago 

 July, 1914 



