1915] BARTLETT—MUTATION IN OENOTHERA 113 
Turning again to table XII, it is seen that the progenies might 
possibly be assembled in two groups, those with a mutation ratio 
of approximately 400:1 (group I of table XIII), and those with a 
ratio of about 250:1 (group II of table XIII). Testing separately 
the ratios from these groups (see table XIII), we find that the num- 
ber of individuals in group II is too small to establish a significant 
deviation from the ratio for group I. (The difference is 0. 180.13 
per cent). It is therefore impossible to demonstrate either that 
the mutation ratio is or that it is not the same for all the progenies. 
TABLE XIII 
TEST OF THE FITNESS OF THE MUTATION RATIOS TO THE NEAREST MENDELIAN 
RATIO (235:1) 
: PJ ale 
of [8 | 2 [deleae) we | 
S as o Rea ooMw 
be | 82 | fe | Hale 17) See | Bag 
Culture Ee 2 = So Bi s es S30 ges 
a| CFs | Hy Be Si = $63 558 
2 Bos aa ES Sb Bug sok cao 
2} sas | 38 56 g~ |S & 2S: c=hom} 
oOo} oO S) Za n = 5 a 
Lex. A-F, II | 99.63 | 0.37 | 1,083 | 6.07 | 0.18 |o.3940.19|0.02+0. 26 
Lex. A-F, IT | 99.58 | 0.4 9 | 6.47 | 0.24 |o.39t0.24/0.03 £0.34 
Lex. B-F, 09.77 | 0.23 1,776 | 4.79 | 0.11 |o.39+0.15}0.16+0. 29 
Lex. C-F, 99.74 | 0.26 | 4,221 | 5.10 | 0.08 |o.39+0.10/0.13+0.13 
Lex. C-F, 00:77 | 0.2 7,902 | 4.79 | 0.05 |0.39+0.07/0 1640.09 
Lex F-F, 09.57 | 0.43 231 5.42 | 0.42 |o 3940.41/0.0440.59 
Lex. G-F, 99.78 | 0.22 | 1,821 | 4.68 | 0.11 |o.39£0.15)0.1740.29 
age de T| 99.56 | 0.44 | 458 | 6.59 | 0.31 |0.3940.29|0.05 0.43 
ex. I-F IT} 99.53 | 0.4 6.86 | 0.36 |o.39+0.25)/0.08+0.4 
Group 99.76 | 0.24 | 15,720 | 4.89 | 0.04 |0.3940.05)0.15+0.06 
Group IT 99.58 | 0.42 | 3,126 | 6.47 | 0.12 Jo.39+0.11/0.03+0.16 
, Groups I & II -| 90.75 | 0.25 | 18,846 | 5. 0.04 |0.39+0.05\0.14+0 
Total 99.75 | 0.25 | 19,766 | 5.00 | 0.04 |o.39+0.04/0.14+0.06 
If we assume that it is justifiable to treat all of the progenies as one 
group, the numbers are then large enough to indicate, not however 
without considerable doubt, that the frequency of occurrence 
of mut. nummularia is not in accord with the tetrahybrid ratio 
255:1, but with some ratio lying between 330:1 and 450:1. Of 
course we cannot assume that there is no mortality at all among 
the seeds which produce mut. nummularia. If in the 30 per cent of 
seeds O. pratincola which never germinate even when fresh the mor- 
tality among mutations and non-mutations were the same, then 
the mutation ratio would not significantly deviate from 255:1. It 
