Tlie TJuory of Evolution 51 



hippus in a series, for these names stand not for single species, 

 but for groups containing no less than six species under 

 Protohippus, fourteen under Equus, twelve under Mesohippus, 

 and twenty under Hipparion. Fleischmann concludes : " The 

 descent of the horses has not been made out with the precision 

 of an accurate proof, and it will require a great deal of work 

 before we get an exact and thorough knowledge of the fossil 

 forms. What a striking contrast is found on examination be- 

 tween the actual facts and the crude hopes of the apostles 

 of the descent theory ! . . ." 



In so far as this criticism of Fleischmann 's applies to the 

 difficulties of determining the past history of the horse, it may 

 be granted that he has scored a point against those who have 

 pretended that the evidence is simple and conclusive ; but we 

 should not fail to remember that this difficulty has been felt 

 by paleontologists themselves, who have been the first to call 

 attention to the complexity of the problem, and to the diffi- 

 culties of finding out the actual ancestors of the living 

 representative of the series. And while we may admit that 

 the early enthusiasts exaggerated, unintentionally, the im- 

 portance of the few forms known to them, and went too far 

 in supposing that they had found the actual series of ances- 

 tors of living horses, yet we need not let this blind us to the 

 importance of the facts themselves. Despite the fact that it 

 may be difficult and, perhaps, in most cases, impossible, to 

 arrange the fossil forms in their relations to one another and 

 to living forms, yet on an unprejudiced view it will be clear, 

 I think, that so far as the evidence goes it is in full harmony 

 with the theory of descent This is especially evident if we 

 turn our attention to a part of the subject that is almost 

 entirely ignored by Fleischmann, and yet is of fundamental 

 importance in judging of the result. The series of forms 

 beginning with the five-toed horses and ending with those 

 having a single toe has not been brought together haphazard, 

 as Fleischmann's comparison might lead one to suppose, but 



