74 





ii'-X.o;^ ;i.oXa.^/^ ^oxa-VA^ a-5--3or 40-5^^/^ 



The tetrasroric structures in a single Gorus are of 

 very various r.ges. While the first-formed tetraspores are 

 developing, nev/ tetre.si^ore motlier cells Bjce "being formed 

 nearer the cross v.a,ll betv/een the vegetative cells, tlie 

 older tetrasi'Ores being cea^ried av/ay from the cross parti- 

 tion by the grov/th and the stretching of the v/all of the 

 vegetative cell. A longitudinal section of a sorus shows 

 primary tetrasporic cells being formed very near the point 

 of junction of the vegetative cells; outside these are the 

 older tetraspore motlier cells; farther out mature spores 

 are to be seen; while farthest from tlie center occur the 

 involxicral rays (fig. 144). 



The number of tetraspores produced in a single sorus 

 is quite laj'ge . The average number in v/ell developed sori 

 was found to be about 300. 



The process of nucleair o.ivision in the tetrasjore 

 mother cell of Griff ithsia offers ^'lany striking points of 

 difference from the sajne stages in the life liistory of 



