28 THE GENESIS OF SPECIES. [Chap. 



But some of tlie cases which liave heen brought forward, 

 and wliich liave uict witli very general acceptance, seem 

 less satisfactory when carefully ;iiialysed tlian they at first 

 appear to be. Amongst these we may mention " the neck 

 of the giraffe." 



At first sight it would seem as though a better example 

 in support of " Natural Selection " could hardly have been 

 chosen. Let the fact of the occurrence of occasional, 

 severe droughts in the country wliich that animal has 

 inlinbited be granted. h\ tliat case, when the ground 

 vegetation has been consumed, and the trees alone remain, 

 it is plain that at such times only those individuals (of 

 what we assume to be the nascent giraffe species) whicli 

 were able to reach high up w^ould be preserved, and would 

 become the parents of the following generation, some 

 individuals of which would, of course, inherit that high- 

 reaching power which alone preserved their parents. Only 

 the high-reachim'- issue of these hii;h -re aching individuals 

 would again, ccderis paribus, be preserved at the next 

 drought, and would again transmit to their offspring their 

 still loftier stature ; and so on, from period to period, 

 through ?eons of time, all the individuals tending to revert 

 to the ancient shorter type of body, being ruthlessly 

 destroyed at the occurrence of each drought. 



(1.) But against this it may be said, in the first place, 

 that the argument proves too much ; for, on this supposi- 

 tion, many species must have tended to undergo a similar 

 modification, and we ought to have at least several forms, 

 similar to the giraffe, developt^l from different Ungulata.^ 



1 The order Unguhda contains the hoofed l>ctists ; tliat is, nil oxen, deer, 

 jintelope.s, sheep, goats, camels, liogs. the hi}»itopotarntis, the ditlcrent 

 kinds of rhinoceros, the tapirs, horses, asses, zeliras, (iUiiggas, &c. 



