Cope. | 182 [Nov. 2, 
Descriptions of Extinct Vertebrata from the Permian and Triassic Forma- 
mations of the United States. 
By E. D. Cope. 
(Meeting of the American Philosophical Society, November 2d, 1877.) 
The Triassic formation of North America has yielded many of the rep- 
tilian types which characterize the horizon in other parts of the world. A 
Labyrinthodont has been recognized in North Carolina, and I have deter- 
mined the existence of the genus Belodon in the formation in both that 
State and Pennsylvania. Of Dinosauria three types occur in both Europe 
and North America. The Paleosaurus of the former country is represented 
by the American Clepsysaurus, and Zanclodon is somewhat similar in den- 
tal characters to the Zatomus of North Carolina. Of genera with com- 
pressed teeth which have a lenticular section, and both edges denticulate, 
Bathygnathus has been found in North America, and Cladiodon and Ter- 
atosaurus in Europe. This type has, however, been wanting heretofore 
from the extinct Triassic fauna of Pennsylvania and North Carolina. The 
present communication introduces it for the first time from the former 
State, under a form generically different from any of the preceding, and 
with the name 
PALAOCTONUS APPALACHIANUS. 
The specimens on which this determination rests, were found by my 
friend Charles M. Wheatley, A. M., in one of bis copper pyrites mines. 
The most characteristic are two teeth which differ somewhat from each 
other in form. One of them has a greater transverse, and less anteroposte- 
rior diameter, indicating an anterior position in the series. The other is 
more compressed, and presents a greater anteroposterior width. Judging 
by the analogy of the genus Lwlaps, this tooth occupied a position poste- 
rior to the first one. The two were found in close proximity, though not 
in actual contact, in a fragile, argillaceous portion of the copper-bearing 
rock. 
The profile of the anterior tooth is regularly conic with a slight recurva- 
ture, which is not seen in the apex, but in the basal portion of the crown, 
and in the root. The section is almost semicircular at all points, but the 
inner and flatter face is slightly convex ; rather strongly so at the apex. 
The denticulation of the edges is minute, measuring M. .00033. It con- 
tinues to the base of the crown both fore and aft. At this point the edges 
are as elsewhere, at one side of the anterior and posterior aspects. There 
are no ridges nor facets on the crown, and the enamel possesses an obsolete 
minute rugosity of short linear ridges. 
The crown of the second tooth is not only flatter and wider than that of 
the first, but is lit'le more than half as long. Both edges are crenate to 
the base. The marked peculiarity of the tooth is seen in the division of 
the crown into facets by angular ridges. The convex face is divided into 
two, an anterior-looking and a posterior-looking, the former half as wide 
