THE TRANSLOCATION OF PROTOPLASM 167 



cylindrical wall ; a passage-way having thus' been made, the (ab) 

 nucleus passes from one cell to the other ; and this mode of making 

 and using a passage-way is employed in respect to each of a long 

 series of septa which must be passed through or passed by as the 

 (ab) nucleus moves along (AB) hypha several centimetres in length. 



When watching haploid hyphae of Coprinus lagopus being 

 diploidised, 1 1 never once observed a bulging of hyphae at a septum 

 which had to be passed by a nucleus, nor did I see any septa disappear. 



In my Volume IV, in discussing the diploidisation process, I 

 accepted Lehfeldt's conclusions ; but now, as a result of my own 

 observations upon, and a study of the literature upon, the structure 

 of septa in the Higher Fungi, I feel that Lehfeldt's work needs 

 verification before it can be accepted. 



The work of Wahrlich and others (already reviewed), supported 

 by my own observations, has taught us that there is an open pore 

 in the middle of each septum, not only in Ascomycetes, but also in 

 Hymenomycetes such as Coprinus atramentarius, Merulius lacry- 

 mans, and Rhizoctonia solani (= Corticium solani) (Figs. 51, 52, 

 and 74, pp. 95, 96, and 145). If cytoplasm can pass through these 

 septal pores there seems to be no reason why nuclei should not 

 pass through also. Passage of a nucleus through an open pore 

 would be the line of least resistance ; and I now wish to offer the 

 suggestion that, during the diploidisation process in the Hymeno- 

 mycetes, the open pores are actually used for the passage of nuclei 

 from one cell to another. 



We know that, in a basidium, the four haploid nuclei resulting 

 from the division of the fusion nucleus pass up from the basidium- 

 body through the exceedingly narrow necks of the four sterigmata 

 (cf. Fig. 75, p. 148) into the four spores. During their passage the 

 nuclei become extraordinarily constricted and drawn-out. Since 

 nuclei can pass through sterigmatic necks, a priori there seems to 

 be no reason why they should not pass through septal pores during 

 the diploidisation process. 



1 W. Lehfeldt, " Uber die Entstehung des Paarkernmyzels bei heterothallischen 

 Basidiomyceten," Hedwigia, Bd. LXIV, 1923, pp. 237-241. 



