A PHYSIOLOGICAL CHARACTER. 



35 



a better treatment of the data is secured by considering it by unit 

 groups larger than a single brood. Convenient units of comparison 

 are month and two-month periods, and summaries of the data by 

 such periods will be referred to rather than the data by broods. 



Tables 5 and 6 give, in successive columns, the two-month 

 periods; the generations of descent during the periods; the number of 

 broods used in selection; the total number of young tested; the 

 average number of individuals per brood; the average age of the 

 mothers at the time their first broods were produced; the average 

 number of young per day of the mother's age at the time of produc- 

 tion of the first brood — the reproductive index; the total number of 

 individuals moving to the negative end of the tank; the number of 

 individuals failing to reach either end of the tank during the time of 

 the test (15 minutes); the average minimum reaction-time for the 

 different broods; the average maximum reaction-time; the sum of 

 the individual reaction-times (for computation purposes) ; the mean 



Table 5. — Selection data summarized by two-month periods for Line 695 plus. 



Time period. 



Apr.-May 1912. 

 June- July 1912. 



Aug.-Sept. 1912. 

 Oct.-Nov. 1912. 

 Dec. 1912-Jan. 1913 

 Feb.-Mar. 1913 . . 

 Apr.-May 1913.. 

 June-July 1913.. 



Aug.-Sept. 1913.. 

 Oct.-Nov. 1913. . 

 Dec. 1913-Jan. 1914 

 Feb.-Mar. 1914. . . 

 Apr.-May 1914... 

 June-July 1914. . . 



Aug.-Sept. 1914... 

 Oct.-Nov. 1914. . . 

 Dec. 1914-Jan. 1915 

 Feb.-Mar. 1915. . . 

 Apr.-May 1915... 

 June-July 1915. . . 



Aug.-Sept. 1915... 

 Oct.-Nov. 1915. . . 

 Dec.1915-.Jan. 1916 

 Feb.-Mar. 1916. . . 

 Apr.-May 1916... 

 June-July 1916... 



Aug.-Sept. 1916... 



9-12 

 13-19 



20-23 

 24-29 

 30-35 

 36-42 

 43-50 

 51-58 



59-67 

 68-75 

 76-83 

 84-89 

 90-98 

 99-105 



106-114 

 115-122 

 123-130 

 131-138 

 139-145 

 146-153 



154-160 

 161-166 

 167-174 

 175-181 

 182-187 

 188-195 



196-200 6 



28 

 23 



17 

 14 

 62 

 56 

 67 

 35 



74 

 66 

 50 

 56 

 75 

 40 



97 

 106 

 66 

 85 

 81 

 43 



26 

 107 

 80 

 70 

 67 

 49 



89 



9.5 

 3.0 



2.0 

 2.3 

 10.3 

 8.0 

 8.4 

 3.9 



7.2 

 8.4 

 7.0 

 9.3 

 8.2 

 6.1 



8.2 

 12.5 



8.4 

 11.6 

 10.0 

 10.5 



6.6 

 17.7 

 12.4 

 10.3 

 11.7 



9.0 



9.7 



bI 





^•.3 -73 



11.8 

 8.7 



13.7 

 11.2 

 9.0 

 8.3 

 7.8 

 7.2 



6.7 

 7.5 

 7.9 

 8.3 

 7.1 

 6.3 



6.6 

 7.5 

 7.1 

 8.3 

 8.6 

 7.9 



9.2 

 8.4 

 8.5 

 7.9 

 10.4 

 7.2 



6.6 



T3 . 

 ; T3 O 



^a ^ 



Q. (S 



0.81 

 .34 



.15 



.21 

 1.14 



.96 

 1.08 



.54 



1.07 

 1.12 



.89 

 1.12 

 1.15 



.97 



1.24 

 1.67 

 1.18 

 1.40 

 1.16 

 1.33 



.72 

 2.11 

 1.46 

 1.30 

 1.13 

 1.25 



1.47 



189 

 479 



158 

 167 

 77 

 158 

 100 

 209 



114 

 133 

 253 

 158 

 198 

 149 



15 



125 



111 



114 



180 



216 



138 

 74 

 84 

 91 

 88 



163 





679 

 722 



418 

 316 

 428 

 447 

 331 

 462 



548 

 474 

 822 

 634 

 766 

 693 



783 

 776 

 6U 

 664 

 876 

 723 



566 

 662 

 643 

 664 

 787 

 612 



11600 

 13760 



5660 

 3268 

 13761 

 16930 

 13345 

 12355 



20737 

 16019 

 25253 

 24443 

 32718 

 15033 



43400 

 35712 

 20726 

 26122 

 34741 

 15561 



9530 

 25300 

 19710 

 18570 

 22090 

 21200 



414 

 598 



333 

 233 

 222 

 302 

 199 

 353 



280 

 243 

 50, 

 436 

 436 

 376 



447 

 337 

 314 

 307 

 429 

 362 



367 

 236 

 246 

 265 

 330 

 433 



244.04 

 240.92 



249.77 

 101.40 



31.11 

 33.88 



40.86 

 18.28 



23.96 



279.77 

 267 . 64 



173 900 42430 477 338.61 24.21 



206.09 



288.31 



20.97 

 27.53 



32.60 



15.54 



27.78 



» Including all the data available, some of which is additional to that for the broods tested. 

 ''AH available data is here used, including that for the No. 2 mothers whose broods were not ordinarily 

 tested for use in selection. 



