The “ Sexuality ” of the Mucorinece. 217 
by the double use of the word “ sexual.” In its wide sense the term 
is applied to any reproductive process in which there is a union 
of cells, i.e., a union of gametes. In its narrow sense, in which 
it is more satisfactorily used, it is applied only to those cases of 
reproduction in which there is a differentiation of the fusing 
gametes, the gametes being thus of two sexes. As a result of the 
use of the term in its wide sense we have so-called sexual pro¬ 
cesses in which there is not the slightest differentiation of sex. 
Owing to the great need of a word to include all reproductive 
processes which exhibit gametic union, without reference to the 
differentiation or otherwise of the gametes, Hartog 1 suggested the 
term syngainy, with its adjective syngamic. Unfortunately this word 
had been used in another sense by Poultoiff and published a few 
weeks earlier than that of Hartog. The use of syngumy in Hartog’s 
sense must thus be given up, but it may, I think, satisfactorily be 
replaced by the term syngainety, with its adjective syngametic, as 
suggested to me by Professor Poulton. A true sexual process is, 
in this terminology, only a special case of syngamety. 
That the formation of zygospores in both heterothallic and 
homothallic forms is a syngametic process no one would deny, but 
that the process is sexual (in the narrow sense) admits of very 
considerable doubt. *Blakeslee speaks of the heterothallic forms as 
being uni-sexual and the homothallic as bi-sexual. Although there 
may be something to be said for the uni-sexual nature of the 
heterothallic forms, it cannot be admitted that the homothallic 
are bi-sexual. There is no evidence that they are otherwise 
than in the undifferentiated condition as regards sex, which appears 
to be the primitive condition of all organisms. We do not apply the 
term bi-sexual to the monoecious species of Vauclieria , even 
though such forms bear sharply differentiated male and female 
cells. The fact that a homothallic mycelium will hybridize with 
both strains of a heterothallic form is no evidence that it is of 
bi-sexual nature; it would appear to indicate that it is different 
from them both, owing, no doubt, to its undifferentiated nature. 
It is really doubtful whether the term bi-sexual has any definite 
significance as applied to an organism. The term uni-sexual is 
also unsatisfactory, as applied to the mycelia of heterothallic 
forms. 
When we study the evolution of sex, which is so well 
1 Quart. Jour. Micros. Science, March, 1904 ; published April. 
1 Presidential Address, Entomological Soc., Jan. 1904; published 
March. 
