No. 507] DARWIN'S "ORIGIN OF SPECIES" lby 



This view, which implies great breaks or discontinuity in the series, 

 appears to me to be improbable in the highest degree (p. 201). 



Such statements appear to be contradictory, until it is 

 remembered that the kind of new species meant by Mivart 

 would involve such violently sudden changes as the three- 

 toed Hipparion giving rise immediately to the one-toed 

 horse; or the wing of a bird suddenly appearing in 

 place of the fore-limb of some dinosaur. 



Indeed, it seems to be to be demonstrable that the 

 statement of Darwin's views respecting variation requires 

 but little change to bring them into harmony, or, at least, 

 make them include, the origin of varieties by mutation. 



By abrupt variations which are yet not greater than 

 a single variety may show, he means such cases as the 

 six-fingered Kelleia family, or the ancon ram. It is of 

 this kind he is speaking when he says : 



Excluding such cases of abrupt variations, the few which remain 

 would at best constitute, if found in a state of nature, doubtful species, 

 closely related to their parental types. 



On the other hand, it is clear that he included under 

 ordinary variations some, at least, which may now be 

 called mutations. Thus: 



Although very many species have almost certainly been produced by 

 steps not greater than those separating fine varieties; yet it may be 

 maintained that some have been developed in a different and abrup 

 manner. Such admission, however, ought not to be made without 

 strong evidence being assigned (p. 203). 



This is probably as good a place as any to call attention 

 to the fact that in the title of the book the theory is not 

 stated to be the origin of species by the natural selection 

 of favored individuals, but by the natural selection of 

 favored races. Morgan's term the survival of species 

 does not appear to me to be any improvement on this. 

 To my mind a still better statement is that which stands 

 at the head of a syllabus of lectures by Professor James 

 D. Dana, "On the Theory of the Origin of Species 

 through Natural Causes. " 



Resuming the citations, the following explicit state- 

 ment is illuminating: 



