1877.] 581 [Cope. 



malian epiphysis was derivetl. The sculpture of the surfaces is coarser 

 than that to which epiphyses are attached in the Mammalia. Tlie name 

 of the genus expresses this character. 



It is altogether prohable that this genus embraced terrestrial animals, 

 with powerful fore- and hind-limbs subequally developed. The typical 

 species is of gigantic proportions. 



Dystroph^us vi^mal^, Cope. 



In the supposed sternum of this animal (which I have not seen, but 

 which was sketched by Professor NewberrjO, a rather small, slender and 

 compressed process projects from near the middle of one of the sides at right 

 angles to it. Only two of the lateral processes are represented as complete. 

 The longer is subspatulate ; the shorter subacuminate. The scapula pre- 

 sents three complete borders, — the proximal and two lateral ; but the distal 

 is not known. Without it, the length is two and one half times the breadth. 

 The point of junction of the longer (and perfect) short border with one of 

 the long borders, is much thickened, terminating in a mass of bone which 

 is unfortunately broken, but whose section in the line of the end border is 

 a wide oval. From this point, the plate thins away to the various borders. 

 The greatest thickness is nearer the border which terminates in the en- 

 largement described. This surface is then gently convex in transverse sec- 

 tion, while the opposite one is concave to a less degree. It is thicker at the 

 middle than at tlie anterior border in a longitudinal direction. 



The proximal extremity of the humerus is much expanded. The greater 

 tuberosity is a huge crest, as prominent as the head, and separated from it 

 by a marked concavity which constricts the mass connecting it with the 

 head, thus forming a neck. This concavity extends about one-third the 

 length of the shaft. On the opposite side of the head a similar concavity 

 excavates the shaft, separating the internal from the interior ridge. The 

 latter is in its middle portion as prominent as the external ridge, and ex- 

 tends as far downwards. The extensive external face of this part of the 

 bone is nearly flat. 



The internal ridge descending from the head, continues into the poste- 

 rior border of the interior face of the shaft. The great tuberosity continues 

 into the single external ridge of the shaft, which is thus near the middle tri- 

 angular in section, the base of the triangle internal. The external extremity 

 of the distal end is therefore an angle, and the internal a convex side, 

 shorter than the anterior and posterior sides. A ligamentous groove marks 

 the posterior border of the extremity at a point measuring one-third of its 

 length from the external angle. The expanse of the distal extremity is not 

 more than three-fourths that of the proximal. The entire bone so resem- 

 bles a tibia, as to have induced' me to refer it at first to that element The 

 characters of the proximal end are such as to render such identification 

 highly improbable. Such reference would also require that the distal ex- 

 tremit}' should have a fore and aft direction, an arrangement incompatible 

 with the tibia. 



PROG. AMER. PHILOS. SOC. XVI. 99. 3u 



