1908] GATES—REDUCTION IN OENOTHERA 27 
pairs, whether from an end-to-end or side-by-side union of somatic 
chromosomes, or in any other manner, so that this question holds no 
necessary relation to the method of reduction. On the common 
cytological assumption that the chromosomes are qualitatively 
different (which has apparently been shown to be a fact in certain 
well-known cases in animals, that need not be cited), germ cells 
would occasionally arise lacking both members of a pair, and hence 
lacking the possibility of developing certain qualities. In this manner 
it is conceivable that a series of types might arise from the parent 
O. Lamarckiana, each lacking the possibility of developing a certain 
group of characters possessed by O. Lamarckiana. 
On this view, which is suggested merely as a tentative hypothesis, 
we would have in the mutations of O. Lamarckiana an analytical 
process in which a series of types arises from the parent form, each 
lacking in a different group of qualities or capacities which the parent 
form possessed. This does not apply to O. gigas, however, which will 
be taken up at another time. The further bearings of this hypothesis 
on the mutation theory of DeVries will not be followed up in this 
discussion, but it may be pointed out here that such a hypothesis 
accounts for the absence of reversions of the mutants to O. Lamarcki- 
ana, and it may also account for some of the peculiarities of 
hybridization among the Oenothera mutants. I should therefore sug- 
gest that there may be a relation between the type of reduction in any 
organism and its variation and hybridization phenomena. 
In Galtonia and probably also in Tradescantia there are apparently 
the same possibilities that both chromosomes of a pair may occasion- 
ally enter the same daughter nucleus. In other plant forms studied 
the attraction between chromosomes seems to be strong enough to 
keep the members of a pair together until their separation in the 
anaphase of the heterotypic mitosis. The segregation of the members 
of a pair into separate germ cells is thus insured. In cases where, 
as in Oenothera, the members of a pair do not always remain in 
contact, but are loosely arranged on the spindle, such a result as 
already suggested seems certain to occur in certain instances. 
It has already been mentioned that occasionally one chromosome 
goes to the wrong pole of the heterotypic spindle. This is found to 
be the case particularly in the hybrids, for example, in the O. Lamarcki- 
