126 SAMUEL WENDELL WILLISTON— LULL. [M ""Tv?uxvn; 



BIRDS, FISHES, AND MAMMALS. 



Prof. Williston concerned himself but little with the birds, largely because of their rarity 

 in the geologic levels with which he was most familiar. He did, however, make a few observa- 

 tions on their derivation in 1879, 2 wrote on the dermal covering of Hesperornis in 1S96, 23 and, 

 in 10 pages of his Kansas Cretaceous report, 1898, 36 summarized the birds from the Niobrara Cre- 

 taceous. In his list of Kansas birds he follows Marsh's erroneous lead of including Hesperornis 

 in the Ratitae; he feels, however, that the mere possession of teeth is not enough to justify its 

 inclusion in a separate group, and the name Odontornithes is in consequence abandoned. A 

 restoration of Hesperornis based upon Marsh's figure of the skeleton is included. 



Williston's study of fishes is comparable to that of birds — the result of his association 

 with the Kansas Chalk. He does little with the class, and that little does not greatly advance 

 our knowledge, as in certain of the other groups. His study of the Tertiary mammals is of like 

 character, and in no sense ranks with his masterful researches on the aquatic reptiles of the 

 Cretaceous and upon the Permian tetrapods. 



PERMIAN VERTEBRATES. 



Williston's first essay on the vertebrates of the Permian appears in 1897 " and is based upon 

 a small collection obtained in the excavation of a well in Cowley County, Kans., from near the 

 base of the Permian as defined by Prosser. Another paper in the same year 33 describes a laby- 

 rinthodont tooth from the Kansas Carboniferous which has the same curious infolded structure 

 as in the case of Mastodonsaurus of the Old World Trias. Two years later 51 appeared a third 

 paper on the Paleozoic Tetrapoda, this time on the genus Eryops Cope, mainly on the morphology 

 of the coraco-scapula, with a note and illustration of the lower jaw in addition. 



After another five years 72 came a valuable morphological and phylogenetic discussion 

 entitled " The Temporal Arches of the Reptilia." This was invoked largely by the work of Prof. 

 Osborn on the reptilian subclasses Synapsida and Diapsida, which appeared the previous year; the 

 main dissension on Williston's part is as to the use of the term Synapsida proposed by Osborn 

 for the group of reptiles with a single temporal arch, "since this group really does not differ in 

 any essential respect from the Synaptosauria (in the wider sense) of Furbringer and'differs from 

 the Synaptosauria of Cope, as most recently denned by him, chiefly in the inclusion of the 

 Cotylosauria." Williston goes on to say (p. 175) : "But I believe that Cope was right in sepa- 

 rating the two groups, since he recognized, as does Osborn, the ancestral relations of the Cotylo- 

 sauria to both the single and double-barred reptiles." 



Furthermore, Williston can not accept as definitely proved or even probable the conclusion 

 that the reptiles are really diphyletic, since the turtles seem to have had an independent origin 

 from the cotylosaurs. Cope's scheme of relationships, published in 1S96, seems to express 

 fairly well Williston's views of reptilian phylogeny at this time. 



The work on water reptiles, 1914, contains the following (p. 15): 



It may be said decisively that no classification of the reptiles into major groups, into superfamilies or subclasses that 

 has so far been proposed is worthy of acceptance; there is no such subclass as the Diapsida or Synapsida, for instance, 

 and we have very much more to learn about the early reptiles before any general classification of the reptiles can be 

 securely founded. [See table facing p. 133.] 



Hence, the significance of Williston's study of the Paleozoic forms which we are discussing. 



In a "Notice of some new reptiles from the upper Trias of Wyoming," 1904, 71 Williston 

 describes four new genera and species of reptiles from a horizon which he calls the Popo Agio 

 beds. The material is meager for either generic or specific identity, and no conclusions other 

 than suggestions of relationships are given. In 1908, he published at least three papers on the 

 Paleozoic tetrapods, one on Lysorophus, 80 a Permian Urodele, the skull of which he discusses and 

 figures at some length, showing the creature to have been of snakelike body, with feeble powers 

 of vision, probably perennibranchiate, bare-skinned, and more or less mud-burrowing in habit. 

 He does not believe that the genus stood in direct ancestral relationship with the living Necturus 



