INDUCED CHARACTERS IN ASPLANCHNA AMPHORA 351 



series, although of common descent, were of different morpho- 

 logical types and also of what we have called two different poten- 

 tials or different physiological states artificially produced from 

 what was at the start an apparently homogeneous parthenoge- 

 netic stock. The purpose of the experiment is to see whether the 

 advent of sexual reproduction at the beginning of each of these 

 series will have obliterated these different potentials, or in other 

 words, whether the four series derived in these two different 

 manners will be different or identical when maintained and bred 

 under identical conditions. These four contrasting series were 

 reared as follows : From H one hundred and forty-five generations ; 

 from /, eighty; from J, fifty-five; and from K, eighty-seven. 

 Table 1 gives the histories of these four series. 



Examination of table 1 shows the astonishing difference between 

 the two groups — series H and I on the one hand, and, series J and 

 K on the other. Equally striking is the parallelism between the 

 two series in each group. H and / remain alike practically 

 throughout the entire experiment; / and K equally so. It will 

 be seen that H and / are all but homogeneous saccate series. They 

 are as constant as were series D and D 2 recorded in the first paper 

 of these studies. Temporary transitions to the humped type do 

 occur, but they are rare and only at times when the metabolic 

 rhythm was at its height. It should be distinctly stated that H 

 and I were not weak races. 



There were no signs of decadence in either series, even though 

 H was carried to the one hundred and forty-fifth generation. 

 Both series might have been prolonged had time permitted. The 

 average number of young produced per individual approximated 

 closely to sixteen in H and to fifteen in /. 



