THE TRANSLOCATION OF PROTOPLASM 



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Fig. 70. — Rhizopus nigricans. The evacuation of protoplasm from, and the sub- 

 sequent walling-off of, parts of a mycelium during the formation of sporangio- 

 phores and sporangia. The mycelium had developed in a hanging drop of 

 nutrient gelatine, and the hyphae shown had ceased to grow in length. A, a 

 large fixed vacuole v has arisen in the left-hand hypha and is growing in size 

 and thereby pushing the massive labile protoplasm backwards toward a 

 sporangiophore. B, two hours later ; the vacuole has increased greatly in size. 

 C, an hour after B ; a septum (without any central pore) has been formed near 

 the base of the vacuole. The terminal cell, thus cut off, is about to die. 

 Streaming was observed in the protoplasm in the right-hand hypha and 

 irregular longitudinal rotatory movement in the protoplasm bounding the 

 vacuole. D, a main hypha with three side-branches. Through vacuolar 

 pressure, the massive labile protoplasm has been evacuated from the branches 

 a and b, and these exhausted hyphae, which are soon to die, have been walled-off 

 from the main hypha. The branch c is as yet full of protoplasm. E, F, G, 

 and H, four successive stages in the branch c, passed through in about 12 hours, 

 showing the formation of a large vacuole, the consequent evacuation of the 

 massive protoplasm, and the walling-off of the exhausted hypha. Drawn by 

 A. H. R. Buller and C. C. Neufeld. Magnification, 332. 



