28 THE GENESIS OF SPECIES. [CHAP. 



But some of the cases which have been brought forward, 

 and which have met with very general acceptance, seem 

 less satisfactory when carefully analysed than 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 which that animal has 

 inhabited be granted. In that 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) which 

 were able to reach high up would 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-reaching issue of these high -reaching individuals 

 would again, cceteris paribm, 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 aeons 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, developed from different Ungulata. 1 



1 The order Ungulata contains the hoofed beasts ; that is, all oxen, deer, 

 antelopes, sheep, goats, camels, hogs, the hippopotamus, the different 

 kinds of rhinoceros, the tapirs, horses, asses, zebras, quaggas, &c. 



