24 



CHARLES A. COBURN 



born, (the parents usually being removed), until they had 

 attained the age at which the fifth test would ordinarily be 

 given. Then the five tests were given in the usual way. 



This method was used with 9 individuals of Fia, and with 

 48 individuals of F2a. The results are given in tables 13 and 



TABLE 13 

 Summary of Resitlts of Tests of Old Mice of First Generation Hybrids Fi, of Series A 



Average number tests, 4.00 



Range of tests, 4 First test 



Average age in days: 



First 

 test, 86.55 Average 1 and 2 



Last test, 139.00 



Average all 



9 (old) Fia 



Males and Average 3, 4 and 5. 



Females Last test 



Average number tests, 4.00 



Range of tests, 4 First test 



Average age in days : 

 First 



test, 88.33 Average 1 and 2. . . 

 Last test, 141.00 



Average all 



3 (old) Fia 



Males Average 3, 4 and 5 

 Last test 



Average number tests, 4.00 



Range of tests, 4 First test 



Average age in days: 



First test, 85 .66 Average 1 and 2 



Last test, 138.00 



Average all 



6 (old) Fia 



Females Average 3, 4 and 5. 

 Last test 



WILDNF.SS 



Distribution of mice 

 in grades: 



Av. 1 2 



4.44 



4.11 

 3.30 



2.61 



2.44 



4.66 



4.16 



3 .33 



2.50 

 2.33 



4.33 

 4.08 



2.66 

 2.50 



S.\VAGENESS 



Distribution of mice 

 in grades: 



Av. 



44.44 



33.61 



2.80 



2.00 

 2.00 



4.66 



3.83 



3.00 



2.16 

 1 .33 



4.33 



3.50 



2.70 



1.92 

 2.33 



5 1 

 1 



14. A comparison of the first part of table 13 with the first 

 part of table 4 shows that while the older mice average higher 

 in wildness and savageness in the first test (4.44 and 4.44, 

 respectively, to 3.98 and 3.97), they grade lower in the fifth 

 test (2.44 and 2.00 to 2.75 and 2.04). When the results of 

 the males and the females are separated the above statement 



