1877.] 5<" [Cope. 



On a Dinosaurian from the Trias of Utah. 



By E. D. Cope. 



{Read before the American Philosophical Society, February l&th, 1877. ) 



Dystroph^us, Cope. 



This genus reposes on scanty remains, but which are in good preserva- 

 tion, and which present marked characters. The bones consist of the hu- 

 merus, three metatarsals, some ? tarsals, and the distal end of an ? ulna, 

 with a probable sternum and an inferior element of either the scapular or 

 pelvic arch, probably the latter. There is also a numbor of fragments, 

 which are not easily identified. The specimens were discovered by Prof. 

 J. S. Newberry in South-eastern Utah, while acting as Geologist to the 

 Engineer Exploring Expedition under the command of Captain McComb, 

 United States Army, He ej:cavated them from the red and green rocks 

 usually referred to the Trias, hence from the same formation which yielded 

 the Typothorax already described. Professor Newberry made sketches of 

 the bones as he exposed them. They were all, he states, found in close 

 proximity, the bones of the limb in nearly normal relation. It is alto- 

 gether probable, according to Professor Newberry, that they belong to a 

 single animal. I find nothing to forbid this supposition and much to con- 

 firm it. 



One of the most remarkable bones is a broad, flat element, one of whose 

 borders is digitate, the processes being long, and separated by deeply entrant 

 sinuses. Two sides of the bone are broken away, but the others give ori- 

 gin to five digitiform processes. Two of these are larger and longer than 

 the others, and externally on the right side is a shorter one. Outside of 

 this is a larger process whose extremity is recurved so as to be subparallel 

 with the longer processes, and which was connected with another bone by 

 an articular surface. This information is derived from Prof. Newberry's 

 notes made in the field. It is probable that this bone is the sternum, and 

 that the articulation mentioned is costal. It is not certain whether the 

 longitudinal meridian line passes through a sinus or a digitation, but a pro- 

 jection of the surface of the plate, which is probably median, is opposite 

 one of the latter. Supposing then that the sternum is produced into a 

 median posterior process, we find a resemblance to the corresponding ele- 

 ment in many birds not heretofore known among reptiles. There are in that 

 case three postero-externally directed processes on each side, of which the 

 two posterior are free. Another interpretation might be that it is a cora- 

 coid with anterior digitations. In this case the articulation above men- 

 tioned would be anomalous. The number of digitations is too great for 

 this element, and the space remaining for contact with the sternum is too 

 small. 



Another large flat bone approximates a right-angled triangle in form, 

 the length greatly exceeding the width. The right-angle is massive and 



to 



