BRl-EDING SYSTliMS 



PLANTS 



ANIMALS 



EUROPEANS 



HINDUS 



Fig. 87. — Simplified diagrams showing the comparative non-spatial restrictions of 

 mating in relation to divergence of descent with the various systems of control 

 found in man and other organisms. Black represents exclusion from mating by too 

 close relationship (the inmost circles being selt-fertilization). Circles represent obstruc- 

 tion of mating; broken circles by discrimination against inbreeding, unbroken by 

 selection against remote crossing. Horizontal hatching represents exclusion from remote 

 crossing, diagonal from crossing with the like sex. hi Plants incompatibility of the 

 too-like and the too-unlike arc the agents; in Animals mating discrimination against 

 the too-like and the too-unlike; in Europeans taboos and laws against incest and 

 mating preferences; in Hindus the example illustrated represents the working of 

 high caste rules in North India : the prohibition of inbreeding extends to sapindas, 

 i.e. the 6th cousin on the male side and 4th on the female; outbreeding is also 

 more restricted for females than for males by the hypergamy rules which prevent 

 women but not men marrying beneath them so that the possible mates for a female 

 may be reduced to a small fraction of unity. 



357 



