68 



Its size, form and position strongly indicate that it supported and facili- 

 tated the movements of a large and probably long and prehensile mus- 

 cular tongue. 



The outer surface of the symphysis is rough and irregular, slightly 

 concave, and with an oblique eminence on each side of the middle line. 

 These eminences indicate the place of origin of the retractors of the 

 lower lip. Purchased. 



392. A portion of the malar bone of a Mylodon robustus, showing the de- 

 scending process, which characterizes the existing Sloths and the extinct 

 species of the Megatherioid family. Purchased. 



393. The body and left cornu majus of the os hyoides of the Mylodon robustus. 



The part of the body of the os hyoides included between the articular 

 tubercles for the anterior cornua is short, subcylindrical, and of less ver- 

 tical diameter than the anchylosed posterior cornua. A rather thick and 

 rough convex ridge projects downwards from the anterior extremities of 

 these processes, doubtless for the attachment of strong thyro-hyoidei 

 muscles ; two slight tuberosities on the front of the body, below the 

 articular tubercles, indicate the insertions of the sterno-hyoidei muscles. 



Purchased. 



394. The hyoid articular extremity of the right stylo-hyal bone of the Mylodon 

 robustus. Purchased. 



395. The left stylo-hyal bone of the Mylodon robustus. Purchased. 



390. A fragment of the body of a dorsal vertebra of the Mylodon robustus. 



Purchased. 



397- A fragment of the body of, apparently, the last dorsal vertebra of the My- 

 lodon robustus : it exhibits the deep excavations upon the under surface 

 which are noticed in the description of the skeleton. Purchased. 



398. The bodies of the three anchylosed lumbar vertebrae of the Mylodon ro- 

 bustus. The flat surface which the first lumbar presents to the last dorsal 

 vertebra corresponds with the form of the same articulation in the en- 

 tire skeleton : the portion of the first sacral vertebra, which is anchylosed 



