RATE OF MOVEMENT OF NUCLEI 227 



(Fig. 128), if after 42 hours there had been a hypha stretching in 

 a perfectly straight line from the inoculum to the farthest point 

 reached by the (ab) nuclei (as shown by the appearance of clamp- 

 connexions), the hypha would have been 6-0 cm. or 60,000 [x long 



or — '- = 12,000 times its own diameter. The width of a nucleus 



5 



when passing along a hypha must be less than the width of the hypha, 



i.e. in the case under consideration less than 5 /x. Assuming that 



the width of each moving nucleus was 4 fi, then a nucleus which 



took our supposedly straight-hyphal course would have travelled 



— '. = 15,000 times its own width in 40 hours, or 375 times its 



4 



own width in one hour, or 6 • 2 times its own width in one minute, or 



its own width in about every 10 seconds. But, in reality, owing to 



the supposed straight-hyphal course not having been available and 



the actual course having been zig-zag through a three-dimensional 



network of hyphae, the nuclei under consideration must have 



travelled upwards of 6-0 cm. in 40 hours. Supposing that in the 



40 hours a nucleus actually travelled 10-0 cm., then it must have 



travelled 25,000 times its own width in 40 hours, or 625 times its 



own width in one hour, or 10-4 times its own width in one minute, 



or its own width in about every 6 seconds. If the moving nuclei 



could have been seen with the microscope, therefore, they would 



have appeared to move along the hyphae with considerable rapidity, 



(7) The moving nuclei and the septation of the mycelium through 

 which they pass. The haploid mycelium of Coprinus lagopus, like 

 that of other Hymenomycetes, is divided into separate cells by plain 

 septa, but the septa in the species under discussion are arranged 

 at rather irregular intervals along the hyphae. In a hypha of one 

 piece of haploid mycelium there were about 14 septa to one mm. 

 of length. Assuming that, on the average, each mm. of each hap- 

 loid hypha contains 14 septa, a nucleus passing for 6-0 cm. in a 

 straight course through a haploid mycelium {cf. Fig. 128) would be 

 obUged to pass through a hyphal passage-way which initially was 

 provided with 840 septa. 



It seems likely that a nucleus, when travelhng through a haploid 

 mycehum which it is assisting to diploidise, must, on approaching 



