98 



GENETIC VARIATIONS 



of these differences are inherited ; when the individuals repro- 

 duce, their descendants show characteristics like those of their 

 parents. Again, in the well known infusorian Paramecium, 

 one finds a large number of diverse stocks, differing in size. 



M8 



%iSS. 



Figure i6. Inherited differences in Difflugia corona. Six races or 

 biotypes differing in size, number and length of the spines, and in 

 other respects. Each horizontal row is a series of individuals all derived 

 by successive divisions from the individual at the left end of the row. 

 After Jennings, 1916. 



and in other respects. Within each stock there are size differ- 

 ences due to diversity of age and nutrition; but the mean 

 differences are inherited ; they are handed on from generation 

 to generation. 



