1921] BLAKESLEE, CARTLEDGE, & WELCH—CUNNINGHAMELLA 193 
currently applied to the so-called dioecious condition in forms like 
the willow, despite the familiar exceptions. 
Conclusion no. 2, that the sexual races of C. echinulata and 
Mucor V as separated by us are unable to form progametes with 
any of the twenty-six races of C. bertholletiae studied, is too sweep- 
ing a statement, and will be shown later to be incorrect. In place 
of “are unable to form” should have been written ‘have not been 
observed to form’’ progametes. 
The statements of fact in conclusions nos. 3, 4, and 7 are what 
one could make in regard to a heterothallic species. Conclusion 
no. 5, that a condition of hermaphroditism exists in some strains, 
seems somewhat opposed to the fact brought out in no. 6, that 
these hermaphrodites do not themselves take part in conjugation 
when growing alone in pure cultures, ‘‘a fact which indicates that 
this species is not homothallic,”’ according to BuRGER. “Homo- 
thallic” it will be remembered is a term used by us to indicate a 
hermaphroditic condition in gametophytes. The line of reasoning 
is as follows: some strains are hermaphrodites, in none of the her- 
maphroditic strains did branches of the same hyphae conjugate, 
therefore the species is not hermaphroditic. 
Earlier in the paper the fact that the stock tubes containing the 
individual twenty-six races did not produce zygospores under 
nutrient and temperature conditions favorable for their formation 
showed according to BurGER “that the cultures were pure and 
not a mixture of strains.’”’ On the contrary, BURGER’S own data 
show that lack of zygospore formation cannot be a proof of freedom 
from mixture of strains. Table I makes the matter clear. The 
minus race no. 4 fails to form zygospores with the plus race no. ro. 
If nos. 4 and 10 were mixed in a tube culture, therefore, they would 
not be expected to form zygospores, and yet the plus component 
(no. 10) of this mixture would form zygospores with the minus races 
3, 7, 8, etc., while the minus component (no. 4) would form zygo- 
spores with the plus races nos. 9 and 14. The tube containing the 
mixture suggested would be able to conjugate, therefore, with both 
plus and minus strains, and such a reaction is BuRGER’S proof of 
hermaphroditism in Cunninghamella. ‘Table I shows that eighteen 
out of the twenty-six races could be mixed to form twenty different 
