62 



SELECTION IN CLADOCERA ON THE BASIS OF 



During the year (August 1912-July 1913) the means were 

 302.5 and 256.3 seconds. The difference (+46.2 12.1 seconds) is 

 3.81 times the probable error, a difference statistically significant. 

 For the 12 same-day broods the means are 314 and 254 seconds 

 and the difference is +60 21.68 seconds, 2.76 times the probable 



error. 



TABLE 25. Selection summary for Line 719. 



Time period.' 



Apr. 1912- 

 July 31, 1912 



Aug. 1, 1912- 

 July 31, 1913 



Aug. 1, 1913- 

 July 31, 1914 



Test series, 

 May 1914 . . 



Apr. 1, 1914- 

 June31, 1914 



Aug. 1, 1914- 

 June 25, 1915 



Test series, 

 Nov. 1914.. 



Oct. 1. 1914- 

 Dec. 31, 1914 



Strain 



Plus . . . 

 Minus 

 Plus. .. 

 Minus 

 Plus. .. 

 Minus 



Plus . . . 

 Minus 

 Plus. .. 

 Minus 

 Plus. .. 

 Minus 

 Plus. .. 

 Minus 



9-19 

 9-21 

 20-54 

 22-58 

 55-96 

 69-105 



82-93 



90-101 



97-137 



106-145 



110 



118 



105-117 

 11 3-1 4 



5 

 6 

 5 

 7 

 8 

 13 



23/4 



12 



12 



40 



39 



4322. 

 3 



1211. 



794 



450.1 



493. 1 

 302.5 

 256. 3 

 409.6 

 366.3 

 520.8 

 463.6 

 453.7 

 434.5 

 364.2 

 345.0 

 310.9 

 290.6 

 261.1 

 288.1 



275. S 



sos. 4 



232.3 

 142.9 

 257.6 

 966. S 



289.2 

 271. 



264.9 

 239.8 

 217.2 

 197.0 



21.0 

 23.8 

 10.1 



8.9 

 10.9 

 10.1 



9.1 



8.6 



-43.0 

 +46.2 



+43:3 



+'57:2 



+ 1JK2 

 + 19'. 2 



+'26:3 



31.8 

 12.1 



TABLE 26. Same-day broods. Summary of data for Line 719. 



Time period. 



Apr. 8, 1912- 

 July 31, 1912 



Aug. 1, 1912- 

 July 31, 1913 



Aug. 1, 1913- 

 July 31, 1914 



Aug. 1, 1914- 

 June25, 1915 



Strain. 



( Plus.... 

 I Minus . . 



( Plus 



Minus . . 

 ( Plus. ... 

 I Minus . . 



I Plus 



i Minus . . 



-ss 









7is 

 580 



314 



3-1 ) 

 884 

 351 

 978 



257.80 

 320.75 

 262.11 

 44-66 

 207.54 

 249. 6 S 



7 



18.85 

 10.71 

 15.01 

 /7.95 



II 



if 



54.99 +179 



+60 



-64 



-27 



76.002.35 



For the following year (August 1913- July 1914) the means are 

 409.6 and 366.3 seconds. The difference is +43.3 13.2 seconds 

 and is 3.28 times the probable error. Again the plus mean is larger 

 by a margin of statistical value. The 11 same-day broods have 



