PLATE XII. 



Fig. 1. Spongospora-infeeted tuber sprouting feebly. (May, 1909.) 



Fig. 2. Eeproduction of a figure of Protoviyces from Martius's " Die Kartoffel- 

 Epidemie." 



Fig. 3. Eeproduction of a figure from Brunchorst's article on Spongospora Solani, 

 allowing the plasmodia in potato-cells. 



Pig. 4. Microphotograph of plasmodia p, and spore-balls. 



Fig. 5. Microphotograph of plasmodial stage of scab. At c cork cells are visible. 



Fig. G. A little of fig. 5 more highly magnified. Host-cells are seen in various 

 stages of invasion by the plasmodium, e.g., in a, host-nucleus, and 

 starch-grains are still present. 



Fig. 7. Sketches of spore in spore-balls in different stages of development 

 or of germination. (Mostly ^ 2000.) 



