10 



HOESE AND MAN. 



the body, plus the heavy neck and head, and would 

 inevitably be shattered at the first leap. 



Therefore, the humerus of the horse (see J in the 

 figure) is short, thick, and set in a sloping direction, 

 so as to avoid a direct shock as the animal alights from 

 its leap. The reader will notice 

 that the lower end of this bone 

 is enlarged, expanded, and very 

 deeply grooved. 



Next come the two bones of 

 the fore-arm, k being the large 

 bone (radius), and L the small 

 bone (ulna). Both terms are Latin, 

 the former signifying the spoke of 

 a wheel, and the latter an arm. 



Here is a bolder modification 

 than in the humerus. 



It is necessary for man that 

 he should be able to rotate the 

 hand, and therefore the two arm- 

 bones are free at their extremities, and so constructed 

 that they can partially roll over each other. But, 

 for the hand of the horse to be capable of rotation 

 would be an element of weakness, and therefore the 

 bones are so modified that they can only be moved 

 directly backwards and forwards. The ulna, there- 

 fore, is very much reduced in size, and does not 



LEFT ARM (HUMAN.) 



