BUTLER AND KULKARNI. 261 



Fig. 8. Details of the septa, a. A group showing the formation of cellulose 



processes on one or both sides of the hypha. b. Septa in an old hypha, the 

 space between the septa being filled with cell contents, while, above 

 and below it is empty, c. A thin regular septum probably of very recent 

 formation, d. Septum cutting off a lateral branch. The other septa show 

 various types of thickening. X 930. 



Chlamydospores from oat-juice agar. X 330. 



Germination of the zoospores. X 330. 



Germination of a zoospore while still within the sporangium. X 330- 



Germination of a sporangium with direct production of hypha?. 



Two sporangia which have germinated with production of 

 secondary sporangia, the lower one having formed a tertiary also. 

 X 330. 

 Fig. 14. Hypha with sporangia from a corm taken about a month after 



harvest, cut in two and placed in a moist chamber. X 330. 

 Fig. 15. Two sporangia arising from the same stalk, the lower formed after 



the upper, which it has pushed to one side. X 330. 



Plate IV. 



Fig. 1. A mature sporangium with single irregular vacuole and distinct 



papilla. X 630. 



Fig. 2. A sporangium shortly before discharge, showing the spherical 



vacuole. X 630. 



Fig. 3. Escape of the zoospores. On the right two free swimming zoo- 



spores. X 630. 



Fig. 4. Formation of the oogonium on a stalk which has penetrated the 



antheridium. X 930. 



Fig. 5. Ditto, later stage. X 930. 



Fig. 6. Ditto, later stage, the contents of the oogonium having contracted 



to form the oosphere. Antheridium empty. X 930. 



Figs. 7, 8, 9, 10 and 12. Fully formed oospores with persistent antheridia sur- 

 rounding the stalks of the oogonia. The origin of the oogonium on 

 a lateral branch from a hypha is seen in Figs. 9, 10 and 12. X 930. 



Fig. 11. Two oogonia on a common stalk, the branches from which penetrate 



two distinct antheridia. X 930. 



F)g. 13. Mature oospore, showing persistent antheridium surrounding the 



stalk of the oogonium. The antheridia] stalk is visible on the right. 

 Micro -photograph. 



Fig. 14. Ditto, showing type of oogonium with thickened wall. Micro- 



photograph. 

 (We are indebted to Mr. C. M. Hutchinson, Imperial Agricultural Bacteriol- 

 ogist, Pusa, for the micro-photographs reproduced in Figs. 13 and 14, tor which 



a Zeiss 3 mm. apochromatic oil immersion lens was used.) 



