1881. J «^"^ [Cope. 



Measurements of VertebrcB. M. 



AViclth transverse process of atlas 010 



Vertical diameter neural and odontoid canal 015 



Length axis to odontoid process 033 



" odontoid process 007 



(vertic-il | with hypapophysis .012 

 Diam. centrum behind^ (without " .009 



' transverse 0115 



Length of centrum of fifth cervical 030 



" " seventh 017 



" " second dorsal 014 



Anteroposterior diameter of base of neural spine of 



second dorsal 010 



Expanse of head and tubercle of first rib 012 



Fore Limb. — The greater part of the blade of the scapula is lost. The 

 neck is stout, and the coracoid is a short aliform process. The humerus is 

 moderately robust, most so proximally. The greater tuberosity is a strong- 

 ly incurved crest, with truncate summit, which is a little elevated above 

 the plane of the head, from which it rises rather abruptly. The bicipital 

 ridges are not strong nor prominent. The olecranar fossa is deeper than 

 the coronoid fossa, and they communicate by perforation. The inner part 

 of the condyle is the largest, and forms an acute angle with the interior 

 epicondylar surface. The exterior part of the condyle is divided by an 

 obhque angle of the surface separating an external bevelled band of the 

 same, which narrows to extinction on the posterior side. As compared 

 with the humerus of Hyrachyus eximius, that of Triplopus cubitalis is very 

 similar, differing mainly in two points at the distal extremity. The 

 olecranar fossa is smaller and is less excavated, and its lateral bounding 

 ridges are of unequal elevation ; in T. cubitalis they are equal. 



The ulna and radius are more than one-fourth longer than those of H. 

 eximius. Although they are entirely distinct throughout, the ulna is quite 

 slender anterior to the proximal third. The shaft is much more slender 

 than that of HyracJiyus eximius. The olecranon is compressed, deep, and 

 truncate behind. The distal epiphysis is remarkable for its length, being 

 twice as long as that of the radius. The head of the radius is subequally 

 divided by fossse, the external being the shallower. The inferior or ulnar 

 facet is regularly and gently convex downwards, and is bounded behind 

 by a roughened ridge, which, near the external border tui'ns backwards to 

 the humeral border. The shaft of the radius is robust and flattened. The 

 carpal facet of the radius is contracted, and has three times the superficial 

 area of that of the ulna. The scapholunar dividing ridge is present, but is 

 very low. The scaphoid face is the more excavated, and then rolls back- 

 wards, forming a very narrow posterior facet, which is narrower than that 

 found in the species of AnGMtJierium. There is no distinct fossa on its 

 inner or posterior border, as in many ungulates. The trapezium and 

 scaphoid are the only bones of the carpus which are wanting. The latter 



PROC. AMER. PHILOS. SOC. XIX. 108. 2w. PRINTED MAY 16, 1881. 



