DARWIN AND PALEONTOLOGY 219 



are adduced not only in support of the broad in- 

 duction that the fittest survive, but also in proof 

 of the more specific principle of Darwin that cer- 

 tain single organs^ such as certain types of tooth 

 structure, or of foot structure, have been favor- 

 able or fatal to their possessors. This is now 

 capable of statistical demonstration and no 

 longer a matter of highly probable inference, as 

 Darwin left it. The most readily comprehended 

 case is that during the Upper Oligocene and 

 Lower Miocene periods, a large number of en- 

 tirely unrelated quadrupeds possessed a closely 

 similar pattern ^ in their grinding teeth ; it was 

 the one character which they possessed in common 

 and certainly was the one character which led 

 them all ahke to extinction. 



Selection of the larger variations of propor- 

 tion. When we approach the further applica- 

 tion of the selection principle, however, as more 

 novel with Darwin and more intimately asso- 

 ciated with his personal views, namely, his doc- 

 trine of the selection of larger variations of pro- 

 portion, as, for example, in the classic case of the 

 elongation of the neck of the giraffe, we are 

 forced to admit that paleontology neither posi- 

 tively sustains nor destroys this working hypoth- 

 esis, although the evidence which it presents is 

 rather favorable than tmfavorable. 



By exclusion of other hypotheses, paleontol- 



^ I allude to the grinding teeth technically known as bunosele- 

 nodont, that is, with a rounded crown (bimos) on the inner side of 

 the grinders, and crescentic (^selene) ridges on the outer side. 



