MAMMALIA. 



No. 33. Megatherium Cuvieri, Desm. 



15 



Hind-Claw. — Size, 11 x 6. 

 Price, $1.50. 



No. 33. Megatherium Cuvieri, Desm. 



Fore-Claw.— Size, 9x4. Price, $1.00. 



No. 34. Megalonyx Jeffersonii, Harlan 



Skull. The remains of 

 this huge terrestrial Sloth, so 

 called from the great size of 

 its claw, are found chiefly in 

 the Upper Tertiary of Vir- 

 ginia, Tennessee, Kentucky, 

 Mississippi, Alabama, and 

 Texas. The genus was estab- 

 lished by President Jeffer- 

 son in a communication read to the American Philosophical Society, 1797, enti- 

 tled " A Memoir on the Discovery of certain Bones of a Quadruped of the clawed 

 hind in the Western Parts of Virginia." The M. resembled the Megatherium in 

 general form and habits, but was a third smaller. The fossil skull, of which this 

 specimen is a cast, was discovered in a Pleistocene ferruginous sand aud shell -bed 

 near Henderson, Kentucky, and is now in the Cabinet of the late Professor D. D. 

 Owen, New Harmony, Indiana. It has lost its malar bones, the second molar on 

 the left ramus, and the last on the right, but otherwise it is well preserved. The 

 upper outline is nearly horizontal, and the cranium carries a prominent, rugged, 

 sagittal crest. The zygomatic process projects outward and forward at an angle 

 of about 45 ° . The face above is smooth and convex, and tapers forward. As in 

 all the Sloth tribe, the teeth of the M. are long, fangless columns of uniform 

 diameter, deeply excavated from the bottom for the reception of the dental pulp. 

 The transverse diameter of the largest molar is one inch, and its length, five 

 inches. The dental formula of the M. is m. J5 — 18: the first molars beine: 



4 4^ ° 



separated from the rest two inches. Characteristic of the family to which the 

 M. belongs, the teeth are entirely destitute of enamel. — Size, 14 x 7. Price, $4.50. 



