200 REV. J. T. GTJLICK ON DIVERGENT EVOLUTION 



Preliminary Definitions. 



Believing that great obscurity has often been introduced into 

 the discussion of biological subjects by the use of terms of un- 

 certain import, I have endeavoured to obtain greater precision by 

 giving definitions of the terms I have introduced ; and for the 

 sake of indicating what words are thus used with special and 

 definite meanings, they have been distinguished by capitals. A 

 few of these definitions are here given, aud others will be given in 

 the body of the paper. 



All Inter gener ant ^ or Inter generating Group, is a group of 

 individuals so situated and so endowed that they freely cross 

 with each other. 



Regeneration, or Independent Generation. In harmony with the 

 fundamental doctrines of evolution, I assume that each species 

 was at one time a single intergenerant ; but we find that many 

 species are now divided into two or more intergenerants, between 

 which there is little or no intercrossing. This state of freedom 

 from crossing I call Segeneration. Segeneration is of two kinds, 

 Separate Generation and Segregate Greneration. 



Separate Generation, or Separation, is the indiscriminate 

 division of a species into groups that are prevented from freely 

 crossing with each other. 



Segregate Generation, or Segregation, is the intergeneration 

 of similar forms aud the prevention of intergeneration between 

 dissimilar forms. 



Select Generation, or Selection, is the partial or complete 

 exclusion of certain forms from the opportunity to propagate, 

 while others succeed in propagating. The generation of any 

 form is select with reference to the non-generation of forms that 

 fail of propagating, and segregate with reference to the genera- 

 tion of forms that propagate successfully, but separately. 



Adaptational Selection is exclusive generation that depends 

 upon superior adaptation either to the environment or to other 

 members of the same species. 



Natural Selection is the exclusive generation of those better 

 fitted to the natural environment, resulting from the failure to 

 generate of those less fitted. 



Artificial Selection is the exclusive generation of those better 

 fitted to the rational environment. 



Beflfcxive Selection is the exclusive generation of those better 



