LIFK HISTORIES OF FUNGI 



26] 



meet, the dense protoplasm has been cut up into innumer- 

 able, more or less angular masses, each surrounded by a 

 plasma-membrane, and containing from two to six nuclei 



Fig. 187. — Rhizopus nigricans, i. Full-sized sporangium, showing 

 layer of vacuoles nearly formed along the inner surface of the denser plasm, 

 X about 200. 2, Section passing to one side of the sporangiophore, 

 showing columella-clef t being formed by fusion of the vacuoles shown in i , 

 and by a furrow frpm the base of the sporangium, X about 200; 3, Detail 

 of another part of same sporangium as shown in 2, showing early cleavage 

 furrows, X about 850. (After D. B. Swingle.) (Cf. Figs. 186 and 188.) 



each (Fig. 187). These iinally become entirely separated 

 from each other, oval in shape, and surrounded by a cellulose 

 wall, having clearly marked ridges (Fig. 188). They are 



