\ 
686 _ HENRY FAIRFIELD OSBORN 
Among the more important of the new or little-known skeletons — 
were the following, which, to students of the early evolution of the 
skeleton of vertebrates, will ever stand as important types: 
Pariotichus laticeps, Williston 
Trematops milleri, Williston 
Areoscelis gracilis, Williston 
Seymouria baylorensis, Broili 
Casea broilii, Williston 
Mycterosaurus longiceps, Williston 
Trimerorhachis insignis, Cope 
Varanosaurus brevirostris, Williston 
Ophiacodon mirus, Marsh 
These were only the more conspicuous of the many priceless 
specimens which Williston and Miller have brought to light, and 
which the former has described and figured with the most pains- 
taking care and accuracy. ‘This material also enabled Williston to 
give definite and in many cases final figures of the sutural limits of 
the elements of the skull in most of these genera. Many investi- 
gators had attempted to do this from less extensive and complete 
material, but their results were often uncertain in detail and sub- 
ject to important changes and corrections. , 
In tgtr he published from the University of Chicago Press 
his volume, American Permian Vertebrates, which comprises a series 
of monographic studies on some of the genera already noted. This 
work contains many new and original plates. Careful and exten- 
sive definitions are given of the orders Temnospondyla, Cotylo- 
sauria, Theromorpha, and of the included families and genera. In 
the same year, by invitation of Professor Schuchert, Williston exam- 
ined and described the important collection of Permian reptiles 
which Mr. Baldwin had collected for Professor Marsh between 1877 
and 1880, but which had never been thoroughly studied. Among 
other important results of this research was the erection of a new 
family of Cotylosaurs, the Limnoscelidz, to include the skeleton of 
Limnoscelis paludis Williston. In 1912 he published, in collabora- 
tion with Professor Case, a paper on the “‘Permo-Carboniferous of 
Northern New Mexico,” in the Journal of Geology; he also published 
a general review of primitive reptiles in the Journal of Morphology. 
In 1913 appeared a memoir in collaboration with Case and Mehl 
