1.70 Fossil Bones of the Megalonyx. 



The carpus is yet unknown. Of the metacarpus there are 

 three bones from Virginia, supposed to be of the fore, middle, 

 and third toes of the left fore-foot. The same locality furnished 

 the three bones of the middle toe of the same foot ; with the 

 middle and last phalanges of the third, and the last of the 

 second, with a rudimentary bone representing the fourth. The 

 three phalanges just received by the Lyceum belong, as we 

 have seen, to the right fore-foot. 



Of the animals belonging to the same order, whose osteo- 

 logy is best known, the scapula of the Megalonyx most resem- 

 bles, as Dr. Harlan has pointed out, that of the Great Ant- 

 eater, which is itself very different from most of its kindred in 

 the form of this bone. That of the Megalonyx wants the 

 ridge, so like a second spine, which distinguishes the scapula 

 of this Ant-eater. It has also the same foramen, in place of a 

 notch, near the anterior border, which is observed in several 

 others besides these, especially the Sloth and Megatherium. 



In having perfect clavicles the Megalonyx resembled the 

 Megatherium, one species of Sloth, and one Myrmecophaga ; 

 but differs from others of the same families, the Ai having 

 merely imperfect clavicles ; while the two species of Mauis, 

 the Onjcteroims, and two Myrmecophaga, have none at all. 



The humerus of the Megalonyx is materially dissimilar from 

 the same bone in both the Sloths and the Megatherium, with 

 which genera it has been usual to confound this animal. It has 

 neither the excessive length and slenderness of that of the for- 

 mer, nor the short and massive form peculiar to this bone in 

 the latter, which it approaches in the great breadth and flatness 

 of the lower portion. It is much more like the humerus of the 

 Ant-eaters, and especially the Orycteropus, an animal from 

 which, in other particulars, it differs more perhaps than from 

 any other of this order. It is, as in this and other Edentata, 

 but excepting the Sloth and Megatherium, perforated below on 

 the side next the body. 



In the bones of the fore-arm the Megalonyx partakes of the 

 characters of the Sloths and Ant-eaters : but shorter and stouter 



