GEOLOGICAL SOCIETY OF PENNSYLVANIA. 347 



NOTICE OF THE OS ILIUM OF THE MEGALONYX LA(^UEA- 

 TUS, FROM BIG BONE CAVE, WHITE COUNTY, TENNESSEE. 

 By R. Harlan, M.D., &c. 



Plate 21. 



Among several portions of the skeleton of the Mega- 

 lonyx, recently discovered in the above named locality? 

 the only bone of this extinct animal^, not heretofore ob- 

 tained, is the OS ilium. A notice of these remains has 

 already been communicated to this Society, by our zeal- 

 ous a ssociatCj Professor Troost, and will be found at page 

 144 of these Transactions. 



Referring to the accompanying figure for a very accu- 

 rate view of this bone, we need only remark, as a curious 

 distinguishing feature, the acetabulum. This is divided 

 into three distinct articulating facets, by a deep crucial 

 groove; the superior facet being nearly double the size 

 of the two inferior. These deep and strongly marked 

 grooves denote the former attachment of very powerful 

 round ligaments. 



The observations of Dr Troost on the locality of these 

 fossils, render it quite probable that all the bones of this 

 animal, hitherto described as coming from White Cave^ 

 Kentucky, are in reality relics from Big Bone Cave, 

 Tennessee. 



