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 16-28. 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. 



