44 



PIEBALD RATS AND SELECTION. 



Table 30.— Mean grade and number of offspring produced by parents of a particular grade in 

 each generation of the minus selection series, based on Tables 18-^8. The grade of the 

 parents is indicated at the head of each column. In the body of the table is recorded the 

 mean grade of the offspring (in light-faced figures) and the number of offspring (in heavy- 

 faced figures) . 



Table 31. — Results of a first return selection from generation 6, minus series. 



