134 SAMUEL WENDELL WILLISTON— LULL. [Mbmo TvKvii: 



Williston believed, arose by the separation of the squamosal and jugal, and not by a definite 

 perforation of any bone, is the sole character by which the group is ultimately distinguished 

 from the Cotylosauria, its ancestral stock. What further phylogenetic work Williston did for 

 his incomplete book on the Reptilia is not now evident to the reviewer. At present the paper 

 under discussion forms the final published statement by one of the highest authorities. 



But two papers other than reviews came from the press in Williston's final year, one on 

 the evolution of vertebrae, 136 the other, Part III of the "Osteology of some American Permian 

 Vertebrates." 137 The first of these discusses the homologies of the elements of vertebrae, prim- 

 itive and otherwise, with their evolution, and is of great value to the student. The other de- 

 scribes further the genera Eryops Cope, Chenoprosopus Meld and Naosaurus Cope, differen- 

 tiating the last clearly from the closely allied Edaphosaurus. 



GEOLOGY. 



In his geological writings, Williston merely discussed such formations as he was concerned 

 with paleontologically, for he was, like most vertebratists, primarily a comparative anatomist, 

 and concerned with geological matters largely as he was with geographical ones, merely from 

 the standpoint of distribution. He wrote of the Kansas Chalk, of semiarid Kansas, of the 

 Kansas red beds, a summary of Kansas geology for a popular work by Angelo Heilprin, on 

 the Laramie (Lance) Cretaceous of Wyoming, on the red beds and Morrison of Wyoming, and 

 finally, with Case, on the Permocarboniferous deposits of the Southwest. 



MAN. 



A number of papers on man came from the pen of Williston, again largely, one might say, 

 as a by-product of bis other research. They discuss chiefly the occurrences of prehistoric man 

 in Kansas, and he records one of the few authentic instances of the occurrence of human arti- 

 facts with extinct animals in America. He also wrote two papers on human evolution, of 

 which the second, on the birthplace of man, has already been alluded to as an address delivered 

 before the Paleontological Society in 1909 (see p. 118). 



SUMMARY. 



The most notable results of Prof. Williston's research lie, aside from the insects, almost 

 entirely within the groups of Amphibia and Reptflia of the Paleozoic and Mesozoic. Com- 

 pared with the volume and worth of this research, his other work on the fishes, birds, and mam- 

 mals is almost negligible. He taught, however, many biologic, anatomic, and taxonomic truths 

 of far-reaching application, so that a student of vertebrates of any class, either recent and ex- 

 tinct, can not afford to overlook his results. He gave us much that we know of the fauna of the 

 Cretaceous, notably of the pterosaurs, plesiosaurs, and mosasaurs, and to him we also owe a 

 very large part of our exact knowledge of the Paleozoic air-breathers, for his indefatigable work 

 in the field and laboratory, aided by a few, very devoted co-laborers, has brought to light a fauna 

 amazing in its extent and degree of perfection — entire skeletons of forms many of which were 

 either new to science or known in very fragmentary condition. Williston not only gave a very 

 clear understanding of the osseous morphology of the forms under consideration, throwing 

 much light upon such vexatious problems as the homologies of the cranial elements, of the indi- 

 vidual vertebrse, and of the amniotic sternum, but by careful comparative study of existing forms 

 was enabled to restore his creatures in the flesh in a way that, anatomically at least, is thus 

 far above criticism. He discussed at some length the life conditions, feeding and other habits, 

 prowess, and evolutionary adaptations of the forms which he studied, and his knowledge was 

 such that he could generally recognize such resemblances as were the result of convergence and 

 such as actually implied a like heritage. His ideas concerning the phylogenies of the amphibian 

 and reptdian groups developed somewhat slowly, due to his desire that such should be founded 

 upon a considerable body of attested fact. In his final paper on phylogenies, in 1917, he 



