240 ANIMAL LIFE PAST AND PRESENT. 



loss of the outer metacarpals, the hoofs of the corre- 

 sponding digits have likewise gradually diminished in 

 size, till we find them represented in cattle merely by 

 the small and totally useless so-called " spurious hoofs," 

 while in the Giraffe they have totally disappeared. 



These " spurious hoofs " and the metacarpal splints 

 are therefore rudimentary structures, of no possible 

 use to their owners, but of the greatest possible interest 

 to the naturalist, as telling in the clearest and most 

 unmistakable language (if but the lesson be read aright) 

 the story of the gradual evolution of the specialised 

 two-toed foot of the modern even-toed Ungulates from 

 that of a four-toed ancestor. That this history cannot 

 be read the other way forwards, so as to make us re- 

 gard the " spurious hoofs " and the metacarpal splints 

 as the beginnings of functional toes, is obvious from the 

 circumstance that it is only among the later formations 

 that we meet with two- toed Ungulates ; the majority 

 of the early ones being four-toed. One other point 

 worthy of notice is that one of the most specialised 

 representatives of this group the Giraffe has suc- 

 ceeded in totally getting rid of these superfluous rudi- 

 mentary organs, both externally and internally. 



Precisely an analogous series of changes has taken 

 place among the Odd-Toed Ungulates (Rhinoceroses, 

 Tapirs, and Horses), in which the third, or middle, 

 toe and metacarpal are always symmetrical in them- 

 selves. Thus the earliest extinct members of this 

 group were furnished with five complete toes; in the 

 Tapir the first toe (thumb) has disappeared, and the 



