APPENDIX II. 



ON CHARACTERS AS ADAPTIVE AND SPECIFIC. 



IT is the object of this Appendix to state, more fully than 

 in the text, the opinions with regard to this subject which 

 have been published by the two highest authorities on the 

 theory of natural selection Darwin and Professor Huxley. 

 I will take first the opinion of Professor Huxley, quoted in 

 exlenso, and then consider it somewhat more carefully than 

 seemed necessary in the text. 



As far as I am aware, the only occasion on which 

 Professor Huxley has alluded to the subject in question, is in 

 his obituary notice of Darwin in the Proceedings of the Royal 

 Society, Vol. XLIV, No. 269, p. xviii. The allusion is to my 

 paper on Physiological Selection, in the Journal of the 

 Linncean Society, Zool. Vol. XIX, pp. 337-41 1. But it will be 

 observed that the criticism has no reference to the theory 

 which it is the object of that paper to set forth. It refers 

 only to my definition of the theory of natural selection as 

 primarily a theory of the origin, or cumulative development, 

 of adaptations. This criticism, together with my answer 

 thereto at the time, is conveyed in the following words. 



" Every variety which is selected into a species is favoured 

 and preserved in consequence of being, in some one or more 

 respects, better adapted to its surroundings than its rivals. 

 In other words, every species which exists, exists in virtue 

 of adaptation, and whatever accounts for that adaptation ac- 

 counts for the existence of the species. To say that Darwin 

 X 2, 



