1 8 EVOLUTION. 



science of Morphology. One of the most striking 

 proofs of the evolution of present organs from differ- 

 ent pre-existing forms is furnished by the horse. 

 The forelimb of the horse is modelled upon a type 

 similar to that of the arm of man. The upper arm 

 is concealed beneath the skin ; the forearm reaches 

 to the knee, which is the wrist, having only seven 

 bones in it, while man has eight. Man has five palm 

 bones, but the horse seems to have but one — the 

 long shank, or *' cannon-bone," which corresponds 

 to the bone supporting the third finger. Below the 

 fetlock comes this finger with three joints, having its 

 nail enlarged into the hoof. Thus the horse walks 

 upon one finger, the third in man. But alongside the 

 cannon-bone are the two splint-bones, which are 

 proved to be rudimentary palm bones of the second 

 and fourth fingers. The proof of this is that the 

 horse is traced back by means of fossil remains in 

 Europe and India, and is found to have three toes 

 fully developed. In 1870 Prof. Huxley predicted 

 that a five-toed horse would be found, and in Amer- 

 ica a fossil has been discovered with four toes, and 

 the rudiment of a fifth. Each increase of members 

 is found in an earlier series of rocks, showing that 

 the change has been progressive during vast periods 

 of time. 



Thus the present horse is proved to have devel- 

 oped from a five-toed animal. As far back as we 

 can go we find animal forms changing by slow de- 



