RATE OF MOVEMENT OF NUCLEI 223 



hyphae in this region may have been completed a few hours before 

 the last observation was made. 



The greatest rate of movement of the (ab) nuclei through the 

 (AB) mycelium was, as indicated in Fig. 128, 6-0 cm. in 42 hours, 

 or 1-45 mm. per hour. From the 42 hours we ought to subtract 

 a few hours to allow for the time which elapsed between the zero 

 hour when the inoculum {ab) was set on the plate and the time at 

 which the two myceha (AB) and (ab) met and fused. Let us sub- 

 tract two hours only. Then the rate of movement of the (ab) nuclei 

 through the (AB) mycelium becomes 6-0 cm. in 40 hours or 1 -5 mm. 

 per hour. 



The rate of radial growth of the central {AB) mycehum (average 

 for seven days, rings Nos. 2-9 in Fig. 128 was 0-15 mm. per hour, 

 while the rate of movement of the {ab) nuclei through the {AB) 

 mycehum was at least 1-5 mm. per hour. A simple calculation 

 based on these data permits us to conclude that the {ab) nuclei 

 moved through the hyphae of the central {AB) mycehum with a 

 speed ten times as great as the rate of growth in length of the 

 mycehum's peripheral hyphae. 



The central haploid mycehum {AB), hke all other haploid 

 mycelia of Coprinus lagopus, consisted of a three-dimensional net- 

 work of hyphae, the network having been formed by the establish- 

 ment of thousands of hyphal fusions {cf. Figs. 88 and 96, pp. 158 

 and 170). It is true that the leading hyphae of the mycelium, of 

 which there were many thousands, grew radially away from the 

 centre of the mycelium ; but, a little way back from the periphery 

 of the mycehum, all these radial hyphae were connected together 

 laterally by means of their lateral branches. 



Since the large central haploid mycelium {AB) consisted of a 

 three-dimensional network of hyphae, the {ab) nuclei which passed 

 out of the {ab) inoculum cannot have progressed through the {AB) 

 mycehum in straight-hne courses hke those indicated by the two 

 broken hues in Fig. 128 ; rather, they must have taken zigzag 

 courses — moving (let us suppose) first along a radial hypha, then 

 along some more or less tangential bridging hyphae, then along 

 another radial hypha, and so forth. It is therefore not improbable 

 that in 42 hours some of the {ab) nuclei travelled nearly twice the 



