EFFECT OF DIPLOID ON HAPLOID MYCELIA 251 



(3x1 inches). The mycelium on its new culture medium grew 

 well and, after about ten days, yielded a rather large fruit-body 

 which shed an abundance of spores. Some of the spores were sown 

 separately on dung-agar and thus ten monosporous myceUa were 

 obtained. These mycelia were then paired with four tester mycelia 

 (AB), (ab), {Ab), and (aB) of the original parental strain, with 

 results which are shown in Table VI. 



Table VI. 



Coprinus lagopus. Pairings of Four Original H aphid Mycelia with Ten 

 Monosporous Mycelia derived from Ten Spores of a Fruit-body produced 

 on a Large H aphid Mycelium [Ab) after this Mycelium had been 

 diphidised by a Diploid Inoculum {AB)-\-{ab). 



najzloritd 



^^ 



AB 



a 



,(/ Ab 



1 3 8 2 7 10 U 



(xB 



6^6 



From Table VI, it will be seen that the ten monosporous mycelia 

 derived from the fruit-body in the test-tube fall, with one exception, 

 into four groups identical with those of the four testers, namely, 

 (AB), (ab), (Ab), and (aB). The exceptional mycelium No. G, shown 

 in the last column of Table VI, produced clamp-connexions when 

 paired with all the four testers ; and this result was again obtained 

 when No. 6 was mated a second time with all the four testers. 

 Whether or not mycelium No. 6 was a mutation could only be 

 decided by further experiments, but these experiments were not 

 undertaken. 



The analysis just recorded does not support the view that the 

 diploidisation of the mycelium (Ab) in Experiment No. 3 of Table V 

 was due to a " Durchbrechungskopulation " of the kind described 



