194 APPENDIX II—INTENSIVE SEGREGATION. 
same time, or at a somewhat earlier time, what I call prepotential 
segregation will divide the species into two groups that are prevented 
for the most part from intergenerating; and these separate groups, 
gradually coming under the influence of different degrees, forms, and 
combinations of the transforming principles, will in time become 
strongly characterized species. It is not, however, necessary that all 
or any of these forms of transformation should codperate with segre- 
gation in order to produce a distinct species. The accumulated 
effects of segregation, unaided by these principles producing intensi- 
fication, would be sufficient to produce well-defined species; but it is 
impossible that they should often remain unaided. 
7. Utilitarian and Non-IU'tilitarian Divergence. 
The principles of suetude and selection, though they are directly 
related to the development of utilitarian characters, may produce in 
the useful innate characters of isolated sections of the same species 
exposed to the same environment, divergence that is not necessary 
or advantageous; and the effects of the other six principles are often 
not only wanting in but opposed to utility. Assimilational transfor- 
mation includes redundance of growth, which is not always, as well 
as economy of growth, which is always, utilitarian. Unbalanced 
elimination, amalgamation, and fecundity may be advantageous, 
useless, or disadvantageous. We have, therefore, in these six prin- 
ciples of transformation, abundant cause for the introduction of 
non-utilitarian characters; and, when accompanied by independent 
generation, they must be the source of multitudes of non-utilitarian 
divergences. In the earlier stages of divergent evolution the non- 
utilitarian distinctions are more abundant; for in the later stages 
multitudes of them are weeded out by economy of growth, as has been 
clearly pointed out by Mr. Romanes;* and still others through com- 
ing under new conditions in the environment or through some new 
habit of intelligence, become useful endowments, and are brought 
under the preserving and accumulating influence of natural selection 
or of suetude. It should, however, be noted that the development of 
useful specific differences is as much due to independent generation 
as is the development of useless specific differences. Diversity of 
suetude or of selection does not produce divergent evolution unless it 
cooperates with independent generation. 

* Physiological selection, Journ. Linn. Soc., Zo6l., vol. xrx, p. 383. 
