1 74 Orthoplasy 



are being accumulated which finally render the character 

 or function complete enough to stand alone. Illustrations 

 of this 'concurrence,' — as it is called above, — between 

 acquired and congenital characters, have already been 

 given, and others are cited in quotations made from 

 other writers below. The definitions of different writers 

 show differences of emphasis (see especially those of 

 Osborn and Morgan given in Appendix A). 



The theory is described by Headley as ' natural selection 

 using Lamarckian methods ' ( The Problems of Evolutioii, 

 p. 120). Groos, in expounding organic selection, says: 

 *When a species have, by means of accommodations, 

 made new life conditions for themselves, they can manage 

 to keep afloat until natural selection can substitute the 

 lifeboat heredity for the life-preserver tradition ' ( The 

 Play of Man, Eng. trans., p. 283). 



The term 'indirect selection,' ^ which some prefer, has 

 reference to the way in which natural selection comes 

 into operation in these cases, i.e., indirectly through the 

 saving presence of modifications, and not directly upon 

 variations which are useful. Poulton had used the term 

 indirect in its adjective form in the following: 'These 

 authorities justly claim that the power of the individual 

 to play a part in the struggle for life may constantly give 

 a definite trend and direction to evolution ; and although 

 the results of purely individual response to external forces 

 are not hereditary, yet indirectly they may result in the 

 permanent addition of corresponding powers to the species ' 

 (see Appendix A, III.). 



The effectiveness of the method of screening and of so 



1 This term was suggested, I think, by an anonymous writer in the Zoological 

 Record. 



