FOREWORD 



In this book we have the chief results of Williston's half-century of 

 exploration and research in the field of vertebrate palaeontology. 

 Here we find the gist of his earlier researches upon the mosasaurs, 

 plesiosaurs, and pterosaurs of the marine Cretaceous of Kansas, the 

 substance of his later and fundamental discoveries among the primi- 

 tive reptiles of the Permian of Texas, and the epitome of his last, 

 comprehensive survey of the evolution of the Reptilia as a whole. 

 The writing of this book was thus the culminating effort and achieve- 

 ment of his inspiring career.^ Death overtook him before the final 

 revision and completion of this work, but happily not before he had 

 finished the greater part of the text and had made for it with his own 

 pen a large series of new and excellent line-drawings. 



In accordance with Williston's wishes the writer undertook to put 

 his last work in shape for the publisher and to see it through the 

 press. For the long delay since 191 8 there have been too many 

 causes to be profitably set forth in detail. The University of Chicago 

 Press, which had published Williston's earlier books, repeatedly 

 found itself unable to accept this one notwithstanding its good will, 

 and private publishers proposed conditions that were not accept- 

 able, either to the Williston Memorial Committee, or to Professor 

 Williston's family. After much unsuccessful correspondence in vari- 

 ous directions, the sad plight of Williston's still unpublished work 

 came to the notice of Professor Thomas Barbour of Harvard Uni- 

 versity, and through his good offices the Harvard University Press 

 now has the honor of publishing the "Osteology of the Reptiles." 



The new drawings that Williston made for this book have been 

 supplemented by many other illustrations, mostly from Williston's 

 earlier works, which were needed to illustrate the present text. The 

 University of Chicago Press has courteously loaned many of these 

 cuts, while others have been copied from the original pubHcations of 

 the authors to whom they are credited. The American Museum of 



1 For an excellent account of Williston's life and work see Henry Fairfield Osborn's 

 article, " Samuel Wendell Williston, i8s2-igiS," Journal of Geology, Vol. xxvi, 1918, 

 pp. 673-689. 



