56 



which has been applied to a corresponding surface on the metatarsal bone 

 of the third toe. This distal end of the bone has no articular surface for 

 the support of a phalanx, but is as rough as the rest of the non-articular 

 surface of the bone. This bone, therefore, establishes the fact of the 

 absence of first and second toes in the hind-foot of the Megatherium, as 

 represented in the figures of the Madrid skeleton by Bru and Pander. 

 The foregoing fossils of the Megatherium, from 234 to 345 inclusive, 

 were presented by Sir Woodbine Parish, R.H. 



346 A portion of the left temporal bone of a Megatherium, including the 

 base of the zygomatic process and the shallow articular surface for the 

 lower jaw. 



From the cliffs of Bahia Blanca, Patagonia. 



Presented by Charles Darwin, Esq., F.R.S. 



34/. A fragment of a molar of a Megatherium, with part of its socket. 

 From the cliffs at Bahia Blanca, Patagonia. 



Presented by Charles Darwin, Esq., F.R.S. 



Genus Megalonyx. 



The following specimens, illustrative of the osteology of the Megalonyx, are 

 casts of fossil bones discovered in one of the limestone-caverns called " White- 

 cave" in Kentucky, or in " Big-bone-cave" Tennessee ; both which localities 

 are assigned to these fossils by Dr. Harlan, by whom the originals, now depo- 

 sited in the Cabinet of the Academy of Natural Sciences of Philadelphia, have 

 been described and figured*. 



348. A portion of a molar tooth, including the termination of the pulp-cavity. 

 It is slightly curved, in two directions, and resembles the tooth of the 

 Megalonyx tfeffersonii, figured in Cuvier's Ossemens Fossiles, 8vo. ed. 

 1835, pi 216, figs. 13 and 14, in being compressed, with the transverse 



* Medical and Physical Researches, 8vo, 1835, p. 319. pi. xiii. 



