THROUGH CUMTTLATIVE SEGKEGATION. 



233 



Following the form of nomenclature adopted in this paper, I 

 venture to call this principle Fertilizational Segregation. 



It is evident that Segregation of this form depends on diver- 

 gence of character already clearly established, and therefore on 

 some other form of Segregation that has preceded. It is also 

 segregative rather than separative, in that it perpetuates a segre- 

 gation previously produced, which might otherwise he obliterated 

 by the distribution of the different forms in the same district. 

 The form of Segregation that precedes Fertilizational Segregation, 

 producing the conditions on which it depends, must, from the 

 nature of the case, be Local Segregation. Chronal and Impreg- 

 national Segregation, when imperfectly established, might be 

 fortified by Fertilizational Segregation ; but, in the case of plants, 

 these are all dependent on previous Local Segregation. 



(e) Artificial Segeegatiois^. 



Artificial Segregation is Segregation arising from the relations 

 in which the organism stands to the rational environment. As 

 the operation of this cause is familiar, and as it was considered 

 in the last chapter when discussing the effects of segregation, we 

 pass on, simply calling attention to the fact that it is a form of 

 Environal Segregation. 



The Importance of Eis-vironal Segregatioi^. 



"We must not assume that the various forms of Environal 

 Segregation are of small influence in the formation of species 

 because Sexual or Impregnational Incompatibility is a more 

 essential feature, without which all other distinctions are liable 

 to be swept away. The importance of the forms of segregation 

 discussed in this chapter lies in the fact that they often open 

 the way for the entrance of the more fundamental forms of 

 segregation, even if they are not essential conditions for the 

 development of the same. Though myriads of divergent forms 

 produced by Local and Industrial Segregations are swept away 

 in the struggle for existence, and myriads are absorbed in the vast 

 tides of crossing and intercrossing currents of life, the power of 

 any species to produce more and more highly adapted variations, 

 and to segregate them in groups that become specially adapted to 

 special ends, or that grow into specific forms of beauty and 

 internal harmony, is largely dependent on these factors. 



