i86 



E DENT A TA 



basin of the Eio de la Plata. Dr. Leidy has described, from similar 

 formations in Georgia and South Carolina, bones of a closely allied 

 species, about one-fourth smaller, which he has named M. mirabile. 

 Three other South American species have been described ; but M. 

 laurillardi, of Lund, founded upon remains found in Brazil, has 

 been made the type of the genus Ocnopus. 



The following description will apply especially to the best-known 

 South American form, Megatherium americanum. In size it exceeded 

 any existing land animal except the elephant, to which it was 

 inferior only in consequence of the comparative shortness of its 

 limbs ; for in length and bulk of body it was its equal, if not 



Fig. G2. — Skeleton of Megatherium, from the specimen in the Museum of the Royal College 



of Surgeons. x",V 



superior. The full length of a mounted skeleton (Fig. 62), from 

 the fore part of the head to the end of the tail, is 18 feet, of which 

 the tail occupies 5 feet. The head, which is small for the size of 

 the animal, presents a general resemblance to that of the Sloth ; 

 the anterior part of the mouth is, however, more elongated, and the 

 jugal bone, though branched posteriorly in the same way as that of 

 the Sloth, meets the zygomatic process of the squamosal, thus 

 completing the arch. The lower jaw has the middle part of its 

 horizontal ramus curiously deepened, so as to admit of im- 

 plantation of the very long-rooted teeth, the peculiar structure 

 of which has been already described. A skull recently discovered 

 shows that, instead of the wide gap between the extremity of 

 the nasals and the premaxillse exhibited in Fig. 62, there was 

 a prenasal bone, towards which a process extended upwards and 



