110 



langes, the sternum of four articulated pieces, and a part of the ilium 

 and sacrum. 



These specimens apparently belonged to three individuals of the 

 same species. They were found, with portions of a mastodon, in 

 company with numerous tropical vegetable remains. They are fri- 

 able and light, not petrified, but destitute of animal matter. 



The teeth are very similar in structure to those of the Megalonyx, 

 though the pieces of the lower jaw are stouter : the jaws may have 

 contained six or seven teeth on each side. 



The largest os humeri is twenty inches long, and fourteen in dia- 

 meter; it is of a massive structure, and deeply grooved by the mus- 

 cular attachments. In place of a foramen, as in the humerus of the 

 Megalonyx, the exterior surface, near the elbow joint, has a deep 

 groove, for the origin of the flexor muscles. The condyles are of 

 great breadth, as in the Megatherium. The inferior articulating sur- 

 face consists of two facets, one exterior and convex, the other de- 

 scribed by Dr. Harlan as concavo-convex, admitting a ginglymous 

 and rocking motion. 



The cubitus or ulna is a short and strong bone, with strong marks 

 of muscular attachments: this was part of an animal of less size than 

 that to which the large humerus belonged. A peculiarity of this bone 

 consists in the position of its superior articulating surface, which is 

 nearly in the middle of its shaft ; the olecranon process being very 

 long, and extending upwards. The lower articulating surface was 

 articulated with the carpal bones, as well as the radius. The total 

 length of this bone is sixteen inches. 



There are four claws, or phalangeal bones of the fore-foot of a 

 small-sized individual : in general form these bones approach nearest 

 to those of the Orycteropus. 



There are two tibiae belonging to different individuals of different 

 sizes: one is ten inches five-tenths in length, the other ten inches. 

 This is a short, thick and strong bone. Its upper articulating sur- 

 face is nearly a circular concave disc. Its lower anterior extremity 

 is marked by a peculiar deep ovoid depression, or hollow, for the 

 reception of a corresponding hemisphere, projecting upwards from 

 the astragalus; forming together, a structure of joint altogether 

 unique. The motions of the ankle joint were rotatory, but the arti- 

 culating surface of the lower aspect of the astrogalus admitted of 

 ginglymous motion with the os calcis. 



The clavicle and ribs, portions of which only exist, are not distin- 

 guished by any remarkable characters : but the foramen for the pas- 



