242 A CENTURY OF SCIENCE 



of the acceptance of Osborn 's theses by his fellow work- 

 ers in science. 



Since the death of Professor Marsh, Osborn has served 

 as vertebrate paleontologist to the United States Geolog- 

 ical Survey, and has in charge the carrying through to 

 completion of the many monographs proposed by his dis- 

 tinguished predecessor. One of these, that on the horned 

 dinosaurs, has been completed by Hatcher and Lull 

 (1907), another on the stegosaurian dinosaurs has been 

 carried forward by C. W. Gilmore of the United States 

 National Museum, while under Osborn 's own hand are 

 the memoirs on the titanotheres (aided by W. K. Greg- 

 ory), the horses, and the sauropod dinosaurs. Of these, 

 the first, when it shall have been completed, promises to 

 be the most monumental and exhaustive study of a group 

 of fossil organisms ever undertaken. 



As a leader in science, a teacher and administrator, 

 Professor Osborn 's rank is high among the leading verte- 

 bratists. He is remarkably successful in his choice of 

 assistants and in stimulating them in their productive- 

 ness so that their combined results form a very consider- 

 able share of the later literature in America. 



The ninth decade ushered in the work of a valuable 

 group of students, of whom John Bell Hatcher should be 

 mentioned in particular, as his work is done. Graduate 

 of Yale in 1884, he spent a number of years assisting 

 his teacher, Professor Marsh, mainly in the field, collect- 

 ing during that time, either for Yale or for the United 

 States Geological Survey, an enormous amount of very 

 fine material, especially from the West, although he also 

 collected in the older Tertiary and Potomac beds near 

 Washington. In the West he secured no fewer than 

 105 titanothere skulls, explored the Tertiary, Judith 

 Eiver, and Lance formations, collected and in fact vir- 

 tually discovered the remains of the Cretaceous mammals 

 and of the horned dinosaurs which he was later privileged 

 to describe. He then (1893) went to Princeton, which he 

 served for seven years, his principal work being explora- 

 tions in Patagonia for the E. and M. Museum, one direct 

 result of which was the publication of a large quarto on 

 the narrative of the expedition and the geography and 

 ethnography of the region. Going to the Carnegie 



