422 SAMUEL WENDELL WILLISTOX. 



vertebrate fossils for Professor ISIarsh in the western fields during the 

 summer and acting as his assistant in paleontology during tlie winter. 

 In 1885 he became Demonstrator of Anatomy at Yale and from 1886 

 to 1890 Professor of Anatomy. During this time he also practised 

 medicine in New Haven. In 1890 he was called to the professorship 

 of geology in the University of Kansas, where he taught invertebrate 

 and vertebrate paleontology, anatomy and medicine, and was also 

 dean of the ^Medical School. In 1902 he went to the University of 

 Chicago as head of the newly established Department of Vertebrate 

 Paleontology, remaining active here until his death. 



Professor Williston was given no opportunity for research and 

 publication by Professor Marsh; hence, with the exception of a brief 

 paper on " American Jurassic Dinosaurs" published in the Transactions 

 of the Kansas Academy of Science in 1878, his published researches 

 in paleontology begin with 1890. While associated with the Uni- 

 versity of Kansas the majority of his papers appeared in the Kansas 

 University Quarterly. During this time his work c oncerned itself 

 mainly with turtles, plesiosaurs, mosasaurs and pterosaurs from the 

 Permian and Mesozoic of Kansas. At the University of Chicago he 

 could give most of his time to vertebrate paleontology, and here he 

 gradually turned to the more difficult problems of the very early 

 Amphibia and Reptilia. Most of the fossils upon which he worked 

 came from the Texas Permian. This occupied the last decade of his 

 life and in this he probably has made his greatest contribution to 

 science. Two books stand out conspicuously in this last period, 

 "American Permian Vertebrates" 1911, and "Water Reptiles of the 

 Past and Present" 1914. In the latter, especially, Williston not 

 only summarizes the previous knowledge and his latest researches, 

 but gives the information to us in an intensely interesting way. In 

 fact his work on "Water Reptiles " is as absorbingly interesting to read 

 as it is scientifically satisfying in its array of facts. Only a writer 

 thoroughly familiar with the structure and evolution of both past 

 and present reptiles could bring before our eyes so vivid a picture of 

 the swarming seas of the Cretaceous period of earth-history in what 

 is now Kansas. This work is based upon his series of studies, previ- 

 ously published, of Kansas mosasaurs, plesiosaurs, crocodiles, etc., 

 and is animated by the purpose to find out the why of every structure, 

 to reconstruct from the bone fragments the ai)pearance and habitvS of 

 the living animals. Much of his work is illustrated by his own restora- 

 tions of the reptiles and their habitats. At the time of his death he 

 was acti\'ely engaged on a general work on the " Reptiles of the \\'orld. 



