378 
GENETICS: A. M. BANT A 
The point of perhaps greatest importance lies in the findings of sex inter- 
grades in a number of lines of a second species of Cladocera — in fact in five 
out of six lines of that species which have been reared in the laboratory. In 
addition De la Vaulx records 7 what are almost certainly such intergrade indi- 
viduals in Daphnia atkinsoni. These extensions of the known occurrences of 
sex intergrades among Cladocera indicate that a condition of sex intergraded- 
ness in Cladocera is less unusual than the writer formerly supposed — that 
maleness and femaleness are even less exclusive phenomena so far as indicated, 
by morphological characters in Cladocera than was believed. In this ma- 
terial the disturbances of the balance of the factors or sets of factors making 
for sex is less unusual than would seem probable if maleness and femaleness 
were really generally mutually exclusive. 
From such clear cases of sex intermediates one wonders if maleness and 
femaleness are really mutually exclusive in those Cladocera individuals which 
morphologically show no unlike sex characters. It seems extremely probable 
that they are not, particularly in view of the fact that in sex intergrade strains 
apparently normal females frequently produce young of widely divergent 
types of sex intergrades. Even in the 'normal' strains one is certainly justi- 
fied in thinking that maleness and femaleness are not complete and mutually 
exclusive states but that in these apparently normal sex forms, too, sex is also 
relative — differing from the so-called sex intergrades not in kind but merely 
in degree, not qualitatively but quantitatively. 
With the relativity of sex so emphatically shown in hybrid pigeons, in hy- 
brid moths and in different species of Cladocera one wonders if the relativity 
of sex ends with pigeons, gypsy moths and water fleas. There seems every 
reason to think it does not. We are coming to the time when it would seem 
imperative to revise our notions of the fixity of sex. The clear cases of sex 
intergrades or sex intermediates just referred to seem no more nor no less 
illustrations of the relativity of sex than one sees in the 'crowing hen' and 
the 'sitting cock' or in the masculine woman and in the man who in almost 
intangible physical characteristics, in speech, in dress, in tastes and habits of 
behavior, and in methods of thought reveals himself as lacking in something 
which makes for the fully equipped male and as possessing qualities ordinarily 
recognized as characteristics of the female. 
Further it does not seem necessary to suppose that relativity of sex is re- 
stricted to cases in which its very conspicuousness forces itself upon our un- 
willing attention in opposition to our fixed conceptions of maleness and female- 
ness as complete, opposed, and mutually exclusive phenomena. Indeed the 
more reasonable supposition is that sex is always relative, that while most 
sexual individuals of whatever species are prevailingly male or prevailingly 
female every individual may have something of the other sex intermingled 
with its prevailing sexual characters. 
1 Riddle, Oscar, Carnegie Inst. Washington Year Book, 12, 1913, (322) ; also Amer. Nat. 50, 
1916, (385-410). 
