440 Mr. Clift on the Megatherium. 



Of the posterior extremities there are : 



The left femur entire, and the extremities of the right femur. 

 The left tibia, and a portion of the fibula anchylosed to it. 

 I'he left astragalus, os calcis, and os naviculare. 

 Five other bones of the tarsus. 



The portion of cranium includes the superior maxillary and intermaxillary 

 bones; a part of the frontal and part of the nasal bones ; the vomer, and the 

 remains of two superior spongy bones. There is also, among the loose frag- 

 ments, apparently a portion of the descending process of the zygoma of one 

 side. The extremities of the intermaxillaiy and nasal bones are, however, 

 broken off, and the parietal and occipital bones are also deficient. 



The maxillary bones include two sockets, and part of the third, on each 

 side. There are many small sinuses at the fractured surface of the os frontis. 



The vomer increases in thickness anteriorly, and extends the whole length 

 of the specimen, apparently forming, as in the fossil rhinoceros {Rhinoceros 

 tichorh'mus , Cuv.), a complete bony septum narium. There are three infra- 

 orbitary foramina, of an oval form, the largest of which measures nine lines 

 in the long diameter, and six in the short. 



Ft. In. Lines. 

 The length of this fragment, measured obliquely from the fractured surface 



of the OS frontis to the end of the protended intermaxillary bones 1 5 



From the anterior socket to the end of the intermaxillary bone G G 



The greatest breadth at the upper part 8 G 



Breadth between the orbits 7 



The least breadth 5 10 



The depth, or vertical diameter of the cranium at the first tooth 8 



The vertical diameter at the fractured end of the specimen, or opposite the 



third tooth 11 



The palate is very narrow, measuring across, between the first molares. ... 1 6 



Between the second molares 1 



The depth of one of the sockets is 7 



The thickness of the alveolar partitions from three to six lines. 



The teeth are all of one kind, viz. molares^ and of similar structure*. Their 

 number, when complete, is, according to Cuvier, sixteen f, there being four 

 on each side in both upper and lower jaws. 



Of the nine teeth in the present specimen, six can be identified thus : 

 1st, 2nd, and 3rd of both sides of the upper jaw. M. Cuvier J describes them 

 as being of a prismatic form, but this appears to apply only to the anterior 

 pair; the rest are regularly four-sided, the anterior surface being somewhat 



* Plate XLV, fig. 2. f Ossemem Fossllcs, tom. v. PI. I. p. 179. + Ibid. 



