VII 



THE BRYINE^ 



197 



of four central cells and eight peripheral ones. Each of the 

 latter divides twice by intersecting w^alls, so that a group of 

 about sixteen cells (Fig. 96, A) occupies the middle of the 

 endothecium. The eight peripheral cells divide by radial walls, 

 after which each of these cells is divided by a periclinal wall 

 into an outer and an inner cell (Fig. 96, B), and the outer 

 cells divide rapidly by radial walls and form the archesporium. 

 The single layer of cells immediately within, and therefore sister 

 cells of the primary archesporial ones, is the inner spore-sac. 

 The account of the development of the endothecium here 



Fig. 96.- -Three transverse sections of an older sporogonium of F. /lygronetrica, X 400 ; 

 ar, archesporium; /, intercellular spaces. 



given differs slightly from the account of Kienitz-Gerloff.^ It 

 was found first that there was not the absolute constancy in 

 the number of cells given by him ; thus in Fig. 96, A there 

 are only fourteen cells in the inner part of the endothecium, 

 and although there are sixteen cells in the outer row their 

 position is not perfectly symmetrical. Again the periclinal 

 division of the cells of the inner spore -sac takes place later 

 than he states is the case. 



In the eight primary cells of the amphithecium there first 

 arise periclinal walls that divide each cell into an inner small 



^ Kienitz-Gerloff (2). 



