46 



SEX 



we understand it or not) that variations are 

 often correlated. It seems as if one germinal 

 change may have several inter-linked effects. 



FIG. S. The freshwater polyp, Hydra, hanging down from 

 a leaf (L). It is about half an inch in length. The 

 diagram shows the tubular body; the tentacles around 

 the mouth ; the male organs or testes (T) in very simple 

 expression as minute knobs of cells; the ovary (0V), a 

 protruding nest of cells with one ovum (E). 



This idea requires to be extended to the 

 body as a whole. A somatic character, which 

 to begin with had nothing to do with sexual 

 reproduction, may come into its service, and 



