264 Transactions British Mycological Society. 
On the strict (+) and (—) theory of sex, one would suppose 
that if a mycelium a were to yield clamp-connections when 
paired with either 6 or c, the sex of the mycelia 6 and c would 
be identical; so that, if b and c were to be paired, no clamp- 
connections would be formed. But this is not always the case, 
for sometimes we may have clamp-connections developed in all 
the pairs a x b, ax c and b x c. Thus, as shown in Table I, 
mycelium No. 14 forms clamp-connections with both Nos. 23 
and 26; but the mycelia Nos. 23 and 26 are not identical in sex, 
for, as shown in Table II, when paired, they yield clamp- 
connections. With four mycelia instead of three, even greater 
complications may arise. It thus appears that the factors or 
genes for sex in Coprinus lagopus are not of a simple but of a 
compound nature. 
In the fourth column of Table II are given the results of 
observation of fruit-body production for 12 (— —) pairs of 
mycelia. Here again, as in the experiments recorded in Table in 
rapid and perfect production of fruit-bodies was associated 
always with the production of clamp-connections, i.e. with the 
secondary or diploid condition of the mycelium, while the pro- 
duction of imperfect fruit-bodies was associated always with 
the absence of clamp-connections and the retention by the 
mycelium of the primary or haploid condition. 
As a result of the experiments which have just been described 
it became necessary to discard the strict (+) and (—) theory of 
sexual strains for C. lagopus. 
Table III shows the results that were actually obtained when 
seven monosporous mycelia were paired in all the possible ways. 
In this table, for the sake of conformity with similar tables 
made by Kniep for Schizophyllum commune, the (+) and (—) 
signs are introduced, but here they have not the same significance 
as in Tables I and II, for they do not indicate sex but merely the 
presence (+) or absence (—) of clamp-connections in the pairs. 
Table IIIT. Coprinus lagopus: All Possible Pairings of 
Seven Monosporous Mycelia. 
2I 22 23 25 26 27 29 
5 i a ee ne 
22 Se 
23.0 4 Ee = eee 
250 SS ee 
262 4) | Ee eee 
i A 
25. =+ + omy, 7 
When the experiments recorded in Table III were being made, 
a check upon the purity of the seven monosporous mycelia was 
