ACADEMY OF SCIENCES.] PUBLISHED RESULTS. 121 



From necessity he published it at his own expense; it was eight years before the receipts from sales covered the cost 

 of printing, but happily he lived to see this consummation. 



His other papers of his early period, 18S1-1SS9, dealt with Asilidce, Conopidas, Tabanida?, and smaller groups, 

 and especially with Syrphidte, in which his fine monograph of 1SS6 is still in universal use, and by the taxonomic 

 genius of its author has created in the United States an ineradicable belief that the family is an easy one, well adapted 

 for the beginner to publish in; a mistaken belief, but highly complimentary to the monographer. 



From 1890 his more important papers were concerned with tropical Dipt era (Mexico, St. Vincent, Brazil), and 

 with bibliography. As his official duties grew more exacting, he gradually abandoned entomology, but he had as many 

 farewell appearances as an opera singer, for he could not resist the temptation to come back again and again. Even 

 as late as the spring of 1917, when he was visiting the writer and reveling once more in a collection of Diptera, his old 

 enthusiasm came back so strongly that he planned describing some new genera, and in fact did publish one (Annals 

 Ent. Soc. Amer., vol. 10, p. 23). But after 1896 he did little work on the order exceptin preparingthe third edition 

 of his Manual, which cost him two years of arduous work, as he drew S0O figures with his own hand. His deep interest 

 in genera and his very wide acquaintance with them, together with his universally recognized taxonomic ability, 

 made him, in the period 1S90-1900, the peer of Osten Sacken, Brauer, and Mik as a world authority in Diptera. 



PALEONTOLOGICAL RESEARCH.* 



The first of Prof. Williston's paleontological papers appeared in 1878 — a brief discussion of 

 the American Jurassic dinosaurs ' — and was followed in the next year by an expression of opinion 

 on the dinosaurian origin of birds. 2 One or two other dinosaur papers followed at rare intervals, 

 but it was not until 1890 that he began his more intensive study of vertebrate forms. His 

 removal to Kansas in 1890 reawakened, as we have seen, his interest in the fauna of the Kansas 

 Chalk, and the beginning of a series of papers upon these forms resulted, the initial one being 

 on a plesiosaur from the Niobrara Cretaceous of Kansas (1S90). 5 The same year there appeared 

 a morphologic paper on the structure of the plesiosaurian skull, 6 of which, as Williston says, our 

 knowledge had previously been very incomplete. In this paper he announces for the first 

 time the presence of sclerotic bones within the orbit, the single temporal arch, and other im- 

 portant details of structure. The following year saw Williston's attention turned to the mosa- 

 saurs and pterosaurs of the Niobrara, his initial article in each group appearing at that time. 



PTERODACTYLS. 



Williston's first paper on the pterodactyls 7 is based upon a well-preserved specimen of 

 Pteranodon in the Kansas University Museum, and from the skull he argues against the proba- 

 bility of the remarkable elongated occipital crest figured by Marsh and since proved to be correct, 

 although Williston held to his opinion for a long period of years. He also described in detail 

 the hinder extremities, and finally gives a very excellent summary of the anatomical peculiarities 

 of the genus Pteranodon, based upon his own observations and those of Prof. Marsh. 



The second paper by Williston on the pterosaurs is that entitled "Kansas Pterodactyls" 

 (1S92). 9 In this he lists the species of Pteranodon previously described by Marsh and Cope, and 

 those of the genus Nyctosaurus described by Marsh. He then passes to a discussion of the 

 morphology of the skull and pubis of the former genus, followed by a full description of a new 

 specimen of Nyctosaurus gracilis Marsh, which was preserved in the Kansas University Museum, 

 and which served to put the genus on a more secure basis. Finally the author summarizes his 

 views as to the relationship of the pteranodonts, expressing a belief that instead of being confined 

 exclusively to Kansas, as had been thought, they may also occur in Europe in the form of the 

 genus Ornithostoma Seeley. 



In 1893, Williston again wrote of the Kansas pterodactyls, 11 this time stating emphatically 

 his belief, backed by recent publications by Prof. Seeley, of the congenerousness of the forms 

 Ornithostoma and Pteranodon, and the precedence of the former name. He adds that Cope 

 was able to see this while Marsh was not, notwithstanding the latter's wealth of material on 

 which to base an opinion. It is interesting to note, however, that the latest authority, Eaton, 

 in 1910 still holds to the opinion of Marsh, using the name Pteranodon for the American types, as 



* Superior figures in this section refer to theserial numbers of the articles listed under " Paleontology "in the appended bibliography. 



