The Statnre and Chromosomes of Oenothera gigas, De Vries. 537 
is rather surprising siuce I have recently found (Gates 1909) that 
0. Icievifolia has 14 chromosomes 1 ). The quality of dwarfness in 
0. nanella is not connected with the chromosome number for tliis 
form has the same number of chromosomes as Lamarckiana (Gates 
1907 c). 
One further interesting fact shown by the cultures of DeVkies 
(1. c., II p. 420) is that when 0. Lamarckiana is pollinated from 
0. gigas the plants (about 60 specimens developed) all have the 
0. gigas characters. DeVries interpreted tliis result as due to pre- 
potency of the gigas parent, because the pollen was taken from a 
plant just beginning to bloom wliile the Lamarckiana plant was 
nearly through blooming. But all the hybrids would presumably 
have 21 chromosomes, and this is probably a case in which the 
gigas characters dominate in the Fi, all the plants having the gigas 
characters, although they might he expected to be somewhat smaller 
than pure gigas. On the other hand, mutants with fourteen chromo- 
somes when crossed with Lamarckiana usually give alternative in- 
heritance, both parental types appearing in the Fi. The different 
behavior in hybridization further emphasizes the fact that gigas comes 
in a different category from the other mutants. 
II. Size of cells and nuclei. 
In 1905 Boveri made a study of the size relations of cells and 
nuclei in Sea-Urchin larvae containing x, 2x, and 4x nnmbers of 
chromosomes, the x larvae being obtained by artificial partheno- 
genesis or by fertilization of an enucleated egg fragment, and the 
4x larvae by shaking the eggs shortly after fertilization. This pro- 
duces a monaster instead of an amphiaster, the chromosomes divid- 
ing, but failing to separate and remaining in one nucleus. Later 
divisions of this nucleus show the 4x number of chromosomes (1904 
p. 15). From comparative measurements in these larvae, Boveri 
formulated the law (1900 p. 43) “The surface of the nuclei is di- 
rectly proportionate to the chromosome number and hence to the 
chromatin mass”. Further (1. c., p. 48) that “The cell number of 
sea-urchin larvae is inversely proportional to the contained number 
of chromosomes ’. And finallv, since the eggs are of the same size 
The Suggestion lies at hand that this 0. Icievifolia individual may have 
developed from a reduced egg of 0 . gigas parthenogenetically. 
