THE EDENTATA, OK ANIMALS POOE IN TEETH. 117 



side instead of its point in contact with the ground. 

 The bones of the thigh and leg are remarkable for 

 their massive proportions, for their thickness, and 

 especially their breadth in proportion to their 

 length : the femur in both Mylodon and Megathe- 

 rium would rank rather with the " flat " than with 

 the " long " bones. These osseous columns were 

 needed to support the huge, heavy, expanded 

 pelvis. The iliac expansions are the chief con- 

 ditions of the other characteristics of this part; 

 and they are unintelligible save in relation to ade- 

 quate extent of powerful muscles, especially those 

 arising from the crista ilii, the chief of which 

 muscles concentrate their force upon the fore 

 limbs. This indicates that these limbs were put 

 to some unusual work ; and the inferences from the 

 teeth and the hind claw lead to its recognition as 

 the pulling down trees and wrenching off their 

 branches ; but for these operations the pelvis must 

 have adequate fixity, and to the weight and strength 

 of itself and its supporting limbs there is added a 

 tail so developed as to serve as a third support and 

 give the pelvis the basis of a tripod. Without this 

 view of the function of the hind parts of the 

 skeleton, we can only see that the pelvis is so great 

 and, with its caudal appendage, so weighty as to 

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