CHAPTER VII 



SPECIAL CONVERGENCE 



SPECIAL convergence depends upon functional 

 equivalence, which may or may not be accom- 

 panied by partial homology. The different 

 degrees may be expressed in various ways at 

 convenience, according as it is desired to focus 

 attention upon a function or an organ, or upon 

 the systematic position. In the systematic 

 method of arrangement one makes use of the 

 terms employed in classification. Individual or 

 racial convergence refers to those resemblances 

 between varieties of a species such as are 

 familiar in the human race as the so-called 

 " doubles." 1 Specific, generic, family, ordinal, 

 class, and phyletic convergence refer respectively 

 to the species of a polytypic genus, to the 



1 Since the above was written Professor Adam Sedgwick has 

 kindly drawn my attention to a paper by Professor Arthur Keith on 

 " The Position of the Negro and Pygmy amongst Human Races" in 

 Nature^ vol. Ixxxiv., 1910, p.54. Professor Keith thinks that pygmies, 

 who are widely distributed, are "modifications produced locally from 

 the larger negro. . . . The Congo pygmies share all the physical 

 features of the Bantu except size ; the Bushman has the characters 

 of the Hottentot, while the pygmies of the Far East find their nearest 

 representatives in the negroes of Oceania." 



