230 S. W. WILLISTON. 



acters of the vertebrae and skull, characters certainly impossible 

 for a rhynchocephalian. 



Recently, in examining the material in the Chicago collec- 

 tions, the remarkable characters of the vertebrae, so anomalous 

 for any reptile, and utterly unknown in this class from the Per- 

 mian otherwise, aroused my interest and doubt. From the ma- 

 trix containing several series of vertebrae a corner of a bone 

 protruded which I recognized as of a mandible. Under the skil- 

 ful manipulations of Mr. Paul Miller a wonderfully complete and 

 undistorted skull was brought to light. In similar matrix, and 

 associated with vertebrae of the same kind I recognized another 

 mandible and several small, pitted dermal bones, probably be- 

 longing to another type of amphibian, though it is not impossible 

 the scutes were those of LysoropJius. 



That the present species belongs in the genus Lysoroplius from 

 the reputed Permian of Illinois seems tolerably well assured, 

 though the type material of the genus is rather scanty, and not 

 entirely sufficient to resolve doubt. That the species are identical 

 is I believe quite improbable. With this understanding, however, 

 it will do no harm to use Cope's name for both genus and species 

 until such time as more and better material of the species has 

 been obtained from the original or contemporaneous beds. 



Lysorophus tricarinatus Cope. 

 Skull {Y'x^s. 1-3). — The general shape of the skull is that 

 of a four-sided pyramid, pointed anteriorly. The upper surface 

 is nearly plane, very gently convex from side to side, and also 

 longitudinally in front. The sutures are widely separated in the 

 specimen, indicating a loosely joined skull, and the bones are 

 quite smooth, without pittings or mucous canals. The nasals 

 are relatively large bones, with nearly parallel sides, rounded 

 anteriorly. The frontals are also four-sided, the longer sides 

 nearly parallel ; the bone is about twice as long as wide. On 

 either side, beginning at the transversely extended fronto-parietal 

 suture, there is a narrow bone which seems to be continuous as 

 a single element to beyond the middle of the nasals, ending acu- 

 minately in front. This is doubtless the prefrontal of the 

 modern urodeles. The parietals are broad and large bones, like 



