A SEX-FACTOR ANALYSIS 



237 



other hand, are identical in their sexual behaviour. Hence we may 

 conclude that the diploidisation of the large haploid mycelium (^6) 

 after coming into contact with the diploid inoculum {Ab)-\-{aB) 

 was not due to mutation and the introduction of entirely new sex 

 factors such as (Wi^i) but that, at the beginning of the diploidisation 

 process, one or more (aB) nuclei passed into the large haploid 

 myceUum (^6) from the diploid mycelium {Ab)-\-{aB). 



Table IV. 



Coprinus lagopus. Pairings of Four Original Haploid Mycelia with Nine 

 Monosporous Mycelia derived from Nirie Spores of a Fruit-hody pro- 

 duced on a Large Haploid Mycelium [Ah) after this Mycelium had 

 been diploidised by a Diploid Inoculum {Ab)-\-{aB). 



NcLu Lifilcmh fnxmt (Ai) x (AiXaB) 



J- 

 ^1 



c5 



a(/{6 

 Ab{l 

 aB{9 



AB 



3 



ab 



Ab 



/ 5 8 A 6 9 



aB 



Z 7 



Experiment No. 2. In another experiment, similar to the one 

 just described, a large haploid mycelium (AB), which was No. 2 

 of Table I, was diploidised by a small diploid inoculum {AB)-\-{ab), 

 which was derived from the combination No. 2 X No. 6 of Table I. 



The results obtained from Experiment No. 2 were similar to, 

 and were interpreted in the same manner as, those obtained from 

 Experiment No. 1. It was concluded that, at the beginning of the 

 diploidisation process, no mutation took place but that one or more 

 (ab) nuclei passed from the diploid inoculum {AB)-}-{ab) into the 

 haploid mycelium {AB). 



Observations on the Conversion of Haploid into Diploid Hyphae. 

 — A large haploid mycelium (ab), about 5 cm. in diameter, was 

 inoculated at one place on its periphery with a small fragment of 



