EXTINCTION OF SPECIES 399 



species — but is the result of circumstances which may be il- 

 lustrated by the fable of the "oak and the reed;" the smaller 

 and feebler animals have bent and accommodated themselves 

 to changes to which the larger species have succumbed. 



That species, or forms so recognized by their distinctive 

 characters and the power of propagating them, have ceased to 

 exist, and have successively passed away, is a fact no longer 

 questioned. That they have been exterminated by exceptional 

 cataclysmal changes of the earth's surface has not been proved. 

 That their limitation in time, in some instances or hi some 

 measure, may be clue to constitutional changes accumulating 

 by slow degrees in the long course of generations, is possible. 

 But all hitherto observed causes of extirpation point either 

 to continuous slowly operating geological changes, or to no 

 greater sudden cause than the, so to speak, spectral appear- 

 ance of mankind on a limited tract of land not before inhabited. 

 It is most probable, therefore, that the extinction of species, 

 prior to man's presence or existence, has been due to ordinary 

 causes — ordinary in the sense of agreement with the laws of 

 organization and of the never-ending mutation of the geo- 

 graphical and climatal conditions on the earth's surface. The 

 species, and individuals of species, least adapted to bear such 

 influences, and incapable of modifying their organization in 

 agreement therewith, have perished. Extinction, therefore, on 

 this hypothesis, implies the want of self-adjusting power in 

 the individuals of the species subject thereto. 



But admitting extinction as a natural law, which has 

 operated from the beginning of life under specific forms of 

 plants and animals, it might be expected that some evidence 

 of it should occur in our own time, or within the historical 

 period. Eeference has been made to several instances of the 

 extirpation of species, certainly, probably, or possibly, due to 

 the direct agency of man. The hook-billed parrot (Nestor 

 productw) of Philip's Island, west of New Zealand, is, perhaps, 



