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REV. J. T. GULICK ON DIVERGENT EVOLUTION 
CHAPTER 1Y. 
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, Impreg- 
national, and Institutional Segregation. 
It is important to observe that Intergeneration requires com- 
patibility in all the circle of relations in which the organism 
stands ; hut, in order to ensure Segeneration between any two 
or more sections of a species, it is sufficient that incompati- 
bility should exist at but one point. If either sexual or social 
instincts do not accord, if structural or dimensional characters 
are not correlated, if the sexual elements are not mutually 
potential, or if fixed institutions hold groups apart, Intergen- 
eration is prevented, and Segeneration is the result, either as 
Segregation, or as Separation that is gradually transformed 
into Segregation. 
(o) 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. 
I distinguish four forms — Social, Sexual, Germinal, and Floral 
Segregation. 
10. Social Segregation is produced by the discriminative action 
of social instincts. 
The law of social instinct is preference for that which is 
familiar in 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 numbers never become so great 
as to impede each other in gaining sustenance, there will be but 
little occasion for segregation ; but multiplication will lead to 
segmentation. "Wherever the members of a species, ranging freely 
