NEW OR LITTLE-KNOWN PERMIAN VERTEBRATES? 
TREMATOPS, NEW GENUS 
S. W. WILLISTON 
The University of Chicago 
Of the numerous specimens obtained from. the famous Permian 
deposits of northern Texas the past year by the University of Chicago 
Expedition, none is of greater interest than one represented by a 
nearly complete skeleton of a new rhachitomous amphibian allied to 
Eryops, discovered by Mr. Paul Miller at Craddock’s Ranch, near the 
town of Seymour. The specimen was found fully exposed on a 
gently sloping surface, intermingled with the remains of a reptile 
which seems to be of a new genus of Cotylosauria, which will be 
described later. At the time of the discovery it was not suspected 
that more than a single individual was represented by the remains, 
the bones of the amphibian, save of the skull, being almost wholly 
inclosed in a more or less weathered mass of hard matrix. Recogniz- 
ing in the skull some of its peculiar characters, Mr. Miller and I spent 
several hours ina careful search for all possibly recoverable fragments. 
Evidently both skeletons had been, originally, nearly complete as 
preserved in the clay beds, and both were probably close together, 
but erosion has destroyed or mutilated much of the reptile and some 
parts of the amphibian. The separation of some of the parts of the 
amphibian skeleton which had been washed free from their matrix 
from the remains of the reptile has been difficult. Fortunately, 
however, nearly all parts of the amphibian skeleton, save the radius, 
fibula, and most of the tail, were found in anatomical relations in 
the blocks of matrix. 
The incrusting matrix which adhered to most of the bones, while 
fortunately preserving the specimen from ruin, was very hard, requir- 
ing nearly two months of patient work on the part of Mr. Miller to 
remove. That these specimens, which must have been exposed for . 
See “The Cotylosauria,” this journal, XVI, 139; ‘‘Lysorophus,” Biological 
Bulletin, XV, 229; ‘‘Diplocaulus,”’ Transactions Kansas Academy of Science (in press). 
636 
