CLASS ARCHIMYCETES 



25 



1910; Lutman, 1913) they lie singly within the host cell and are liberated 

 on its decay; in Sorosphaera (Schwartz, 1910, 1911; Maire and Tison, 

 1909; Blomfield and Schwartz, 1910; Winge, 1913) they are arranged in 

 hollow spheres; in Sorodiscus (Winge, 1913) they form ellipsoids; in 

 Tetramyxa (Maire and Tison, 1911) they lie in tetrads; in Spongospora 

 (Osborn, 1911; Kunkel, 1915) they are joined in spongy masses and in 

 Ligniera (Maire, 1911; Schwartz, 1914; Fron and Gaillat, 1925; Cook, 









■•■■ i&s-y* 



Fig. 14. — Spongospora subterranea. 1. Host cell with 8 spore balls. 2. Young amoeba 

 in host cell. 3. Amoebae. 4, 5. Plasmodium formation. 6. Beginning of segmentation 

 of the protoplasm. 7. Beginning spore formation. 8. Mature spores. (1 X 700; 2 to 6 X 

 600; 7, 8 X 1,830; after Osborn, 1911.) 



1926, Guyot, 1927) in regular clumps. The last genus does not cause 

 the development of tumors by the host, while all the others cause con- 

 spicuous hypertrophies. Only Plasmodiophora and Spongospora cause 

 disease of economic importance. 



An interpretation of the life cycle of the Plasmodiophroaceae is not 

 yet possible. Except for the unconfirmed work of Prowazek and of 

 Osborn, the location of caryogamy is unknown. Similarly the relation 

 of the sporonts to plasmodia needs more careful investigation. Because 

 of this obscurity, a discussion of the relationships of the Plasmodiophor- 



