Homothallism and monosporous mycelia in Coprinus. 207 
Using the same symbols as before, the sequence may be ex- 
pressed as follows: 
F)—> (S+MM +F)—> (S+MM-—F). 
Thus fruit-bodies of Coprinus lagopus were obtained in 
monosporous cultures for two successive generations. 
Judged by the criterion of the appearance of clamp-connec- 
tions in a mycelium of monosporous origin, Coprinus lagopus is 
homothallic, for clamp-connections developed: (1) on each of 
several mycelia of monosporous origin derived from the spores 
of a wild fruit-body (Plate VI, Figs. 6 and 7), and (2) on each 
of three mycelia of monosporous origin derived from spores 
produced by a fruit-body of monosporous origin. This conclusion 
is confirmed by the fact that clamp-connections also appeared 
on (3) a compound mycelium of polysporous origin derived from 
many spores produced by a fruit-body of monosporous origin 
(Plate VI, Fig. 8). Were Coprinus lagopus heterothallic, instead 
of being homothallic, no clamp-connections should have de- 
veloped on any of the three kinds of mycelia just described. 
Judging by Mlle Bensaude’s illustrations and description of 
Coprinus fimetarius, it seems not improbable that this species 
is identical with the one which, upon the advice of Professor 
Buller, I call C. lagopus. A Coprinus fimetarius distinct from 
C. lagopus and coming up on unsterilised horse-dung has not 
been found at Winnipeg, and my Coprinus lagopus, as Professor 
Buller has proved by comparative cultures, is the same as the 
C. lagopus which so commonly comes up on unsterilised horse- 
dung in laboratory cultures in England. Certainly Mlle Ben- 
saude’s C. fimetarius and my C. lagopus have fruit-bodies which 
appear to me to be identical in external appearance. Even if, 
after all, Mlle Bensaude’s species should prove to be different 
from my C. lagopus, it will be necessary to admit that the two 
species are very closely related; and it is, therefore, not a little 
remarkable that they should behave so differently as regards 
sex, Mlle Bensaude’s species being heterothallic and my own 
homothallic. 
V. COPRINUS STERCORARIUS. 
The third species investigated was the well-known Coprinus 
stercorarius the life-history of which was described by Brefeld*, 
and which is remarkable in that it produces small black sclerotia 
the size of dried peas. After plating out some spores from a wild 
fruit-body, two monosporous mycelia were obtained, which, 
after being transferred to dung-ball tubes in the usual way, 
* QO. Brefeld, Untersuchungen, Leipzig, Heft 111, 1877, pp. 13-67. 
