192 APPENDIX II—INTENSIVE SEGREGATION. 
(7) Amalgamational intension, or segregation and divergence 
through independent amalgamation. 
(8) Fecundal intension, or segregation and divergence throwes 
independent fecundal transformation. 
In groups that do not intergenerate, divergent forces reveal them- 
selves whenever transformation is introduced. If it were possible to 
believe that the effects of independent selection or of independent 
suetude had been completely parallel, it would still be impossible to 
believe that both of these, together with the remaining six principles 
of transformation, would ever so combine as to produce completely 
parallel transformation in isolated sections of a species, even if all 
were surrounded by the same environment. This principle is not 
inconsistent with the introduction of what Professor Hyatt calls 
‘‘representative of parallel characteristics’’ in two or more divergent 
series of forms. What he points out is that, under the influence of 
heredity, similar organisms exposed to similar environments undergo 
similar transformation (Anniversary Memoirs of the Boston Society 
of Natural History, 1880: ‘‘The Genesis) of the Tertiary Species of 
Planorbis at Steinheim,” pp. 24-29). 
In the description of these principles I have used the adjective 
‘“independent”’ to signify that the principle is operating in sections 
of the species that are prevented from intergenerating. Inthe term 
‘independent variation’? Mr. Romanes has already used the adjec- 
tive ‘‘independent”’ as meaning ‘‘when accompanied with the prevention 
of intercrossing.”’ 
6. The Pervasive Influence of the Causes of Transformation and the 
Law of Intension. 
In my paper on ‘‘ Divergent Evolution” I made the statement that 
‘“When separate generation is long continued we have reason to believe 
it always passes into segregate generation with divergent evolution.”’ 
The same thought had been expressed in a previous paper by the 
statement that ‘‘Variation is so strong that all that is necessary to 
secure divergence of types is to prevent their intermingling.”’* The 
certainty that independent generation with transformation will never 
produce parallel, but always more or less divergent evolution is the law 
of ontensive segregation already referred to. Butin addition to this cer- 
tainty there is a very strong probability that where independent gen- 
eration is long continued, transformation of some kind will supervene. 
If there are any species in which the power of cumulative variation has 


* See ‘Diversity of Evolution under One Set of External Conditions.’’ Journ. 
Linn. Soc., Zo6l., vol. x1, p. 499. 
