53 



3. Femur of Elephant. — This comprises only the lower half. 

 It is that of an animal fully adult, and belonged to an individual 

 of small size ; the shaft of the bone is more round than that of 

 Mastodon. Compared with that of the Cambridge skeleton, at 

 corresponding parts, the transverse diameter of the latter is 5^ 

 inches, and the antero-posterior 3 inches ; of the fossil, the first 

 diameter is 4 and the second 2 J inches. The condyles examined 

 from behind are longer in a vertical direction and of a more 

 uniform width in the Mastodon than in the fossil elephant. This 

 animal must have been of very small size — probably not ex- 

 ceeding eight feet in height — and, as it is fully adult, must have 

 been very much smaller than the individual from which the molar 

 was derived. 



4. Lower extremity of a Right Humerus of Mastodon 1 — This 

 belonged to an animal of large size. The outer condyle is par- 

 tially broken off; breadth across condyles 10 inches. 



5. Ulna of the same. 



6. An ultimate or sixth upper molar of Mastodon giganteus, 

 as shown by its gradual contraction from before backwards. It 

 is incomplete ; there are four ridges remaining, but the anterior 

 extremity is fractured. It is thickly invested with crusta 

 petrosa between the bases of the ridges. Its greatest breadth is 

 4^ inches. It diminishes in size from before backwards. 



7. An idtimate loiver molar. — It is longer and naiTower than 

 the preceding, as is usually the case with lower molars compared 

 with upper. 



Length ....... 7f inches. 



Breadth 3f " 



These two teeth have a similar aspect, and may have both 

 been derived from the same individual. 



8. Tibia of Megatherium. — This was from the left side, and 

 consists of the lower half. The inferior extremity is well pre- 

 sei'ved. The inner tuberosity, which is thick, rounded, and in- 

 dented for the attachment of ligaments, exhibits on its posterior 

 face two grooves for the passage of the tendons of the flexor 

 muscles of the foot. These are both much less deep than the 

 groove seen on the corresponding portion of the tibia of the 

 Mylodon. The outer border of the bone is thinner, and presents 

 a rough, fractured surface, caused by the breaking off of the fibula, 

 which, in Megatherium, is anchylosed with the tibial,. 



