i24 / LIONEL TAYLER [august 



to be of more importance than the mere conditions of climate, etc., 

 and inasmuch as climatic selection will largely cease acting as soon 

 as organisms, capable of surviving at all under these altered con- 

 ditions, are produced, it follows that inter-organismal action, which 

 is continuous, must be of more importance in species formation and 

 differentiation of structure. But as organisms which cannot survive 

 under these altered conditions will be eliminated, it follows that the 

 more obvious structural changes will be largely produced by this 

 temporary climatic selection, and this form of selection will be re- 

 markably rapid in its action relatively to the inter-organismal 

 selection. Hence the obvious structural changes induced by climatic 

 selection will have less chance of leaving a geological record behind 

 them than the less obvious variations induced by inter-organismal 

 selection. For this reason certain imperfections in the record are 

 likely, and should be expected, to arise. 



6. That the period of time is too short for such great alterations 

 of structure to have taken place. — As the rapidity or slowness of 

 structural alterations will depend on the local surrounding conditions, 

 it follows that, until some fairly complete record of these local condi- 

 tions is obtainable, no objection as to time limit can be logically 

 raised. 



7. The co-ordination of parts necessary for the development of 

 favourable adaptations. — Spencer has pointed out that co-ordination 



of many parts to form one adaptation is based on a different principle 

 to the cumulative results of many different variations each of which 

 is of selective value, and urged that natural selection is powerless to 

 explain this co-existent adaptation. 



Wallace, in referring to this subject, says : — " The fact, that in all 

 domestic animals, variations do occur, rendering them swifter or 

 stronger, larger or smaller, stouter or slenderer, and that such varia- 

 tions can be selected and accumulated for man's purpose, is sufficient 

 to render it certain that similar or even greater changes may be 

 effected by natural selection, which as Darwin well remarks ' acts on 

 every internal organ, on every shade of constitutional difference, on 

 the whole machinery of life.' The difficulty as to co-adaptation of 

 parts by variation and natural selection appears to me, therefore, to 

 be a wholly imaginary difficulty which has no place whatever in the 

 operations of nature." 1 This criticism does not appear to me to do 

 justice to Spencer's objection ; he would no doubt agree with Wallace 

 that these accessory variations can be developed by selection, but he 

 would go one step farther back and ask why it is that the accessory 

 variations happen to be there to be selected from at all. He would 

 agree to the fact that selection must act on the whole machinery of 

 life, but he would still urge that he is unable to see how it is that all 

 these numerous accessory variations which are necessary to the working 



1 "Darwinism," p. 418. 



