PLATE XXXIX 



Spongospora suhterranea 



All figuresweredrawnwith theaidof acamera-lucidaand withZeiss2 mm. and 8 mm. 

 objectives and oculars No. 4, 6, 8, and 12. 



Fig. I. — A small portion of a spore ball, showing the manner in which the spores 

 germinate. X 1,500. 



Fig. 2. — A portion of a spore ball and a small colony of amoebae that have been set 

 free by the disintegration of the spore walls. X 1,200. 



Fig. 3 .—A semidiagrammatic drawing of a section through a very young sorus, showing 

 the infecting plasmodium as it pushes down between the cells. A few of the cells 

 are already infected. Many of those in contact with the plasmodium are beginning to 

 enlarge. The deep-staining globular bodies are distributed throughout the Plas- 

 modium. X 100. 



Fig. 4. — An infecting plasmodium. The cells are being crowded apart as the 

 Plasmodium pushes down between them. The cell walls are becoming gelatinous 

 and somewhat swollen, but are still intact. Deep-staining globular bodies and a few 

 nuclei can be seen. X 1,000. 



Fig. 5. — A potato cell becoming infected by a plasmodium of 5. suhterranea. The 

 wall has been penetrated and the plasmodium is flowing into the cell. X 850. 



Fig. 6. — A Plasmodium closely applied to the host nucleus. The elongated host 

 nucleus has a large and a small nucleolus, but is almost devoid of chromatin. X 1,200. 



Fig. 7. — A small portion of a plasmodium. Simultaneous mitotic nuclear divisions 

 are shown in metaphase. Spindle fibers are clearly seen, but astral rays and centro- 

 somes are wanting. X 925. 



Fig. 8. — Portion of a plasmodium within an infected cell, showing the dense cyto- 

 plasm around the nuclei and the clearer region between them. X 2,000. 



Fig. 9. — A Plasmodium pushing down between mature cells and causing secondary 

 infection. The deep-staining globular bodies are present. X 1,000. 



