Cope.] -tAi7 [MayO, ].S70. 



Remarks by Edward D. Cope, at Meeting May 6th, 1870. 



Prof. E. D. Cope exhibited the nearly perfect cranium of a Dicynodont 

 Reptile from the Cape Colony, South Africa, which he regarded as diifer- 

 ent from those described by Owen and Huxley. 



The application of the cutting edges of the mandible to those of the 

 upper jaw, was nearly horizontal instead of vertical, as in some marine 

 Chelonia, on which account he regarded it as representing a genus distinct 

 from Ptychognathus, with which it was otherwise identical. This was 

 named Lystrosaurus. 



It was nearest the Ptychognathus latifrons, Owen, but differed in having 

 narrowed, sublongitudinal orbits, with immense pi-otuberances in front of 

 them, a very narrow front anterior to, or below these, with two parallel 

 wide sulci on each side, and a much wider occiput and interorbital region. 

 The middle of the cutting margin of the premaxillary was prolonged into 

 a short beak. The front from the orbital protuberances, and the direction 

 of the tusks, both nearly vertical. The following measurements are 

 given: 



In. Lines. 

 Length cranium (greatest), 7 9 



Width occiput, 8 



'' intertemporal space, 1 10.5 



" interorbital '• 8 7 



" between supraorbital protuberances, 4 8 



" anterior to orbits, 2 o 



" across middle of alveolae of tusks, 



" " internasal space, 



" " temporal fossa, 



Length of " 



•' from hindmost part of skull to orbit, 



" from fore part of orbit to border of premaxillary, 

 Long diameter of orbit, 



•' " no.stril, 



The species was named Lystrosaurus frontosus. The specimen be- 

 longed to the private collection of Dr. E. R. Beadle of this city. 



Portions of several large teeth or tusks enclosed in the Triassic shales 

 and sandstones of Phcenixville, Pa., were exhibited, probably belonging 

 to Dicynodont reptiles. Thej' re]3resented specimens of much larger size 

 than that of the L. frontosus. 



