44 



THE THEORY OF EVOLUTION 



enlarged and strengthened as to support the whole 

 weight of the body; the nail is greatly expanded, to 

 form a hoof, which encloses as in a box the whole 



2Z m zz m 



FIG. 1. Right fore limbs of Man (left); Horse (middle); Ox (right). 

 //. humerus. R. = radius. U. = ulna. C. = carpus. Me. = 

 metacarpals. Digits are numbered with Roman numerals. 



terminal joint of the digit. Beside the single func- 

 tional digit, there are remnants, or rudiments, of two 

 others, the second and fourth of the original series, 

 which are not visible externally and consist only of 

 the long bones of the hand (metacarpals) without 

 free joints or hoofs, and are commonly known as 



