582 
GENETICS: A. M. BANTA 
As suggested above the various mothers in the sex intergrade strain 
differ markedly in the proportion of normal sex forms and sex inter- 
grades while they produce. For example, for a given mother the per- 
centage of males — normal males and definitely male intergrades of all 
grades — varies from 8 or 10% to 100%, the more usual figures being 
45 to 85%. The percentages from the same mother from brood to 
brood vary of course but the sex array and its proportion in the first 
brood provide a basis for an estimate of what is to be expected in future 
broods. 
The main interest in this material would seem to lie in the remark- 
able array of sex forms, the stock in general consisting of perhaps 40% 
normal males and about 8% normal females, the remainder being in- 
tergrades with almost every combination of male and female secondary 
and primary sex characters. More than half the individuals are 
neither wholly male nor wholly female but possess definite morpho- 
logical sex characters of both sexes. The writer has attempted to 
classify these individuals on the basis of sex characters into more than 
twenty classes or grades. A grade at one end of the scale contains nor- 
mal females; at the other end of the scale there is a class of normal 
males. Between these extreme grades are others for the many types 
of sex intergrades. Even this large number of grades is scarcely suffi- 
cient; many individuals occur which are intermediate between these 
grades and can with difficulty be assigned to any of them. 
Sex here reveals itself not as a fixed and definite state but as a purely 
relative thing. No arbitrary classification into males and females is 
justifiable or possible; not only because of the confusing admixture of 
male and female secondary sex characters but also because the same 
individual, even the same sex gland, may develop eggs and sperm at 
the same time or sperm at one time and eggs at another time. 
It seems probable that in this species sex depends upon a number 
of elements (I believe them to be largely or exclusively environmental 
factors) which influence the general physiological whole. In the stock 
which produces the sex intergrades the more usual association and the 
culmination of these influences has become interrupted. There is a 
consequent abnormal physiological balance resulting in haphazard 
combinations of sex-characters and a shifting of the balance one way 
or the other. Sometimes the result is a balance so unstable that in 
certain cases it seems to be shifted within a few days in the same indi- 
vidual or within portions of that individual as indicated by changes in 
the sex products. 
Of secondary interest is the method of origin of the sex intergrade 
