207 



above the zygomatic process appears to be broken off, but the obli- 

 quity of its base renders it improbable that it would be the true 

 frontal process so largely developed. 



The circular pit for the attachment of the stylohyal bone is pre- 

 cisely similar in the Sloths to that in the large fossil genera, and it 

 is somewhat remarkable that Prof. Owen, while describing the cha- 

 racter in these extinct forms, should have made no allusion to its 

 existence in the recent Sloths, even though Cuvier expressly points it 

 out. The tongue is largely developed in this family, and the living 

 sloth may be seen to make great use of it in taking food into its 

 mouth, as was observed by Mr. Ball, in a short communication pub- 

 lished in the ' Proceedings ' some years back. On the other hand, it 

 is long and slender in the insect-feeding tribes, so that the maxinmm 

 degree to which it was developed in the Glossotherium is certainly 

 no indication that such was the food of that remarkable genus. 



Cholcepus, lUiger. 



Intermaxillary bones small, produced anteriorly ; postorbital pro- 

 cess well-developed ; malar bone with a well-marked frontal process, 

 but no zygomatic process, the supratemporal process projecting 

 backwards or bent a little upwards ; pterygoid bones inflated ; 

 crotaphite impression approaching near to the occipital ridge ; tym- 

 panic bone reduced to a simple ring; lower jaw produced ante- 

 riorly, straight below, its condyle depressed ; teeth ^, simple, 

 rounded, the anterior ones in each jaw enlarged, trigonal. 

 C. didactylus. 



Bradypus, Gray. 



Intermaxillary bones reduced or wanting ; postorbital process 

 slightly developed ; malar bone with the frontal and zygomatic pro- 

 cesses slightly marked, the supratemporal process rising obliquely ; 

 pterygoid bones inflated ; crotaphite impression terminating at a con- 

 siderable distance from the occiput ; tympanic bone well-developed, 

 forming a bulla ; lower jaw with a flattened square process m front, 

 deep posteriorly, the lower outUne convex, the condyle elevated ; 

 teeth ~^, simple, rounded, the anterior ones similar, small in the 

 upper jaw. 



B. crinitus. 



In addition to the character of the pterygoids, which, m the absence 

 of actual knowledge, might possibly have belonged to age or sex, I 

 find this species to be clearly distinguishable from those of the next 

 genus by the great distance that intervenes between the posterior 

 termination of the temporal fossae and the occiput, which is much 

 greater in the old specimens even than in the young of the genus ^?-c- 

 topithecus. The occiput also differs from them in being proportionally 

 smaller, of a rounder form ; the digastric fossae converging a httle 

 superiorly, instead of diverging as in the other genus. The lower 

 jaw also presents a character more decided than the anterior pro- 



