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RESEARCHES ON FUNGI 





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main hypha and complete fusion of the clamp-cell and the 

 penultimate cell is about 9 minutes ; and (4) the time which 



elapses between the formation of the 

 septum across the base of the hook 

 and complete fusion of the clamp- 

 cell and penultimate cell (time between 

 stages B and E in Fig. 18, p. 35) is 

 about 8 minutes. 1 



From the data just set forth it is 

 evident that, in Coprinus lagopus, after 

 the first-formed septum separating the 

 ultimate from the penultimate cell has 

 been formed, the penultimate cell of a 

 normal hypha, such as A in Fig. 22, 

 actually is, and the ultimate cell of 

 such a theoretical hypha as B in 

 Fig. 22 would be, without a second 

 nucleus for about 9 minutes. 



Therefore, in Coprinus lagopus, 

 whereas in a normal hypha in which 

 the hook grows backwards there are 

 always two nuclei in the ultimate cell, 

 in an unnatural hypha such as that 

 of B in Fig. 22 where the hook is 

 supposed to grow forward, if the 

 growth-rate were the same as in a 

 normal hypha, there would be in the 

 ultimate cell : two nuclei for 41 minutes, 

 then one nucleus for 9 minutes, then 

 two nuclei for 41 minutes, then one 

 nucleus for 9 minutes, and so on 

 indefinitely. 

 There can be no doubt that the nucleus of a cell has a profound 



1 Records were made of the times at which all the externally visible events in 

 the formation of a clamp-connexion were accomplished. In one instance, the hook 

 took 4 minutes to grow outwards, backwards, and inwards until it touched or almost 

 touched the main hypha, Then there was a pause for 10 minutes (during which 

 conjugate nuclear division was going on) at the end of which period a septum could 



22. — Coprinus lagopus and 

 other Hymenomycetes. A, 

 a diagram to show the dis- 

 position of the nuclei in a 

 diploid hypha during the 

 time a nucleus is im- 

 prisoned in the clamp-cell 

 and just before a clamp- 

 connexion has been fully 

 formed. The hook is 

 directed backwards and 

 there are two nuclei in 

 the apical cell. B, a 

 diagram similar to A, but 

 in which the hook is 

 represented as growing for- 

 wards. Here there is only 

 one nucleus in the apical cell. 



