THROUGH CUMULATIVE SEGREGATION. 
233 
Following the form of nomenclature adopted in this paper, I 
venture to call this principle Fertilizatioual 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 be obliterated 
by the distribution of the different forms in the same district. 
The form of Segregation that precedes Fertilizatioual 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 Fertilizatioual Segregation ; but, in the case of plants, 
these are all dependent on previous Local Segregation. 
(e) Artificial Segregation. 
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 Environal Segregation. 
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. 
