MAMMALIA. 665 



part of Brasil, Peru. Compare on these four species and some others of 

 which the distinction is not yet sufficiently established, Wagner in 

 Archivfur Naturgesch. 1850, s. 367— 387> and in Scheeb. Saugth. Sup- 

 plementband, 5 Abth. 1853, s. 162—173. 



Cholcepus Illig., Bradypus F. Cuv. First molar tootli very long, 

 acuminate, resembling a canine, with tlie inferior placed behind the 



4 4 



upper; remaining molars ^j — ^ , ^vith crown cuneate, worn obliquely 



in front and behind. Fore feet didactylous. Tail none. 



Of this sub-genus one species only is known, which therefore provision- 

 ally may retain the name of Bradypus dklactylus L. The head is more 

 protracted and the fore legs are less elongate than in the three-toed species. 

 A figure may be seen in Scheeber's Saugth. Tab. 65, copied from Buffon 

 XII. PI. I, and a better in Guer. Iconogr., Mammif. PI. 33, fig. 1 ; the 

 skeleton is figured in Pander u. D'Alton Das RiesenfauUhier, Bonn, 1821, 

 Tab. VII. 



Different fossil species belong to the order of the edentates; most of 

 them are found in diluvial deposits and in caves. Some appear to belong 

 to the genus Dasypus. Others form a transition between the two families 

 of edentates, and present in the malar bone, which terminates in a process 

 descending obliquely over the lower jaw, a resemblance to the genus Brady- 

 pus, whilst the bones of the limbs are massive and large. Here belongs 

 the genus Megalmyx Jefferson, Cuv. and Megatherium Cuv. (comp. Cuv. 

 Ann. du Mus. v. pp. 358 — 400, PI. 23 — 25, Recherches sur les ossem. fo&siles 

 VI. pp. 159 — 195). The genus Megatherium is best known of the two. 

 Megatherium Cuvierii was an animal which must have been about 12 feet 

 long and 5 feet high, and of which a skeleton was found not far from 

 Buenos-Ayres at the end of the last century, which is now preserved at 

 Madrid. This skeleton is beautifully figured by Pander und D'Alton 

 Das Riesenfaulthier, Tab. i. 11. Afterwards was discovered the genus 

 Mylodon Owen {Description of the Skeleton of an eoUinct gigantic Sloth, 

 London, 1843, 4H ^»i»- ^^s Sc. nat. 26 S^rie, xix. pp. 221 — 263), of which 

 a skeleton found to the north of Buenos-Ayres is preserved in the collec- 

 tion of the College of Surgeons at London, the genus Glyptodon Owen 

 which more closely follows Dasypus and others. The investigations of 

 Lund in Brasil in the last few years have contributed greatly to extend 

 and multiply our knowledge of these fossil animals. Compare Pictet 

 Traite de Palceontologie, 2 ^d. I. pp. 263 — 278. See Leidy On the extinct 

 Sloth trile of North America ; Smithsonian Co7itrihutions to Knowledge, 1855, 

 Vol. VII. 



Order VII. Glires s. Rodentia. 



Incisor teeth in both jaws two, large, incurved, destitute of roots. 

 Canines none. Molars remote from incisors by an interval, mostly 

 few, rarely more than four in each side of both jaws. Feet ungm- 

 culate, in most pentadactylous. 



