72 ALTERNATION IN THE THALLOPHYTES 



but in both cases half of the nuclei produced are discarded : this would 

 seem to point to some special importance attaching to the division into 



3 I 



*" ''-T-*: ' - . j- x _*"' 



FIG. 41. 



Conjugation of K /loftalciiia, after Klebahn. k, nucleus ; kL\ small nucleus ; gk, l.-ir^r 

 mil Icus ; />y, pyrenoid ; , mucilage. (From OHinanns.) 



four, and by analogy with what is seen elsewhere it would appear probable 

 that the importance lies in a process of reduction accompanying it. What- 

 ever the actual cytological condition may be, at all events this is clear, 

 that, in these strangely similar plants, the tetrad-division of the nuclei 



