DIVERGENT EVOLUTION THROUGH SEGREGATION. 305 
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 pro- 
duced by local and industrial segregations are swept away in the strug- 
gle for existence, and myriads are absorbed in the vast tides of crossing 
~and inter-crossing 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. 
CHAPTER IV. 
DESCRIPTION AND CLASSIFICATION OF THE CAUSES OF CUMULATIVE 
SEGREGATION (continued). 
B. REFLEXIVE SEGREGATION. 
Reflexive segregation is segregation arising from the relations in 
which the members of one species stand to each other. 
It includes three classes, which I call conjunctional, impregnational, 
and institutional segregation. 
It is important to observe that intergeneration requires compatibility 
in all the circle of relations in which the organism stands; but, in order 
to insure segregation between any two or more sections of a species, it 
is sufficient that incompatibility should exist at but one point. If 
either sexual or social instinets do not aceord, if struetural or dimen- 
sional characters are not correlated, if the sexual elements are not 
mutually potential, or if fixed institutions hold groups apart, inter- 
generation is prevented, and se-generation is the result, either as 
segregation, or as separation that is gradually transformed into segre- 
gation. 
(a) Conjunctional segregation, 
Conjunctional segregation is segregation arising from the instincts 
by which organisms seek each other and hold together in more or less 
compact communities, or from the powers of growth and segmentation 
in connection with self-fertilization, through which similar results are 
gained. 
| distinguish four forms, social, sexual, germinal, and floral segre- 
gation. 
10. Social segregation is produced by the discriminative action of 
social instincts. 
The law of social instinct is preference for that which is familiar ir 
one’s companions; and, as in most cases the greatest familiarity is 
gained with those that are near of kin, it tends to produce breeding 
within the clan, which is a form of segregate breeding. If the clan 
never grows beyond the powers of individual recognition, or if the 
H. Mis. 354, pt. 1——20 
