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THE AMERICAN NATURALIST [Vol. XLIX 



that is to say, continuous features and not isolated points. 



The observations which we have been comparing on 

 the origin of new characters in vertebrates, inverte- 

 brates and plants certainly afford some insight into the 

 laws of germinal change wherever we can distinguish 

 between the true germinal expression of a character and 

 its visible modification by ontogeny or environment. 

 Recurring to the antithesis between the separability and 

 the correlation of characters we may again sum up some 

 of the many properties and qualities of single characters : 



Laws of Correlation 

 of Hereditary connection with the 

 or origin of similar characters in 

 el- other lines of descent; strong sex 

 ts correlation in the size and pro- 

 ions of all characters; mechan- 

 correlation both in the al- 

 ?trons and rectigradations; 

 proportion in descendants of compensation correlations when 

 rly related ancestors; develop- one character is developed by the 

 it of similar " rectigradations," sacrifice of another; proportional 



all the new characters and changes 

 of proportion share the general 



Laws of Separability 

 Independent germinal origi 



discontinuous; independent devel- 

 opment of similar new characters 

 in near or remotely related de- 

 scendants of the same ancestors; 

 development of dissimilar changes 

 idants of 

 develop- 



of Waagen," and 

 of De Tries" at dif- 

 in descendants of the 



selection 



whei 



At the present time we appear to understand the laws 

 of separability somewhat better than the laws of corre- 

 lation, for the latter are enveloped in the deepest mys- 

 tery. We have not even alluded to the chemico-physical 



