1 8 Brannon. — The Structure and Development of 



as noted, is the centre of growth of the sporiferous filaments, 

 and the four adjacent cells receive and supply food-material 

 for the development of the sporiferous tissue. In all prepara- 

 tions of a certain stage it was observed that the central cell 

 gave rise to an upper and a lower daughter-cell (Fig. ao b, c). 

 These cells contained the same dense, yellowish, protoplasmic 

 contents which characterized the cell from which they came. 

 The daughter-cells, resulting from the division of the upper 

 cell (Fig. 26 d) multiply rapidly and soon form a papilla {pa) 

 of four to six cells extending from the floor obliquely into the 

 cavity of the cystocarp. The plane of cleavage in the cells of 

 the papilla is not regular but angular and concave on the 

 upper surface of older, and convex on the lower surface of 

 younger cells (Fig. 18). Marginal cells are cut off from the 

 surface of these and give rise to most of the sporiferous 

 filaments (Fig. 33). All of these cells are connected by pits 

 and contain the same dense, yellowish, protoplasmic contents 

 which characterized the auxiliary cells. 



Sporiferous filaments continue to originate at different 

 times, so that in a median longitudinal section of a partially 

 mature cystocarp fully developed spores may be found on one 

 side, and half mature to very young ones on the other (Fig. 2a). 



The sporiferous filaments have a somewhat unique, though 

 uniform, method of development. They usually grow in the 

 form of a central chain of cells, from each unit of which 

 a whorl of branches is developed consisting of two to three 

 cells (Fig. 24). Primarily, the cells of each branch are 

 connected by long protoplasmic filaments (Fig. 18//), but the 

 cells gradually enlarge until this neck-like connexion is so 

 abbreviated that they are almost in contact, showing merely 

 a simple protoplasmic pit in the very short connexion between 

 their walls (Fig. 23/). These enlarged cells become densely 

 filled with protoplasm and give rise to the dichotomously 

 branching chains of carpospores. Usually three to five 

 carpospores originate from each sporiferous branch by 

 repeated abstriction of its terminal portion (Fig. 23 c). At 

 first the carpospores are small, irregular in form (Fig. %6 c), 



