PARASITES OF PROTOZOA 1067 



Geitler found the fungi on a narrowly defined area of the body, the 

 protruding filaments vertical to the surface of the protoplasm and from 

 100 to 200 |_i long. The filaments of a plant are non-septate and arise 

 from a deep-staining, irregularly lobed vesicle, the haustorium, lo- 

 cated in the endoplasm of the amoeba at the limits of the ectoplasm. 

 From the vesicle, which was also noted by Penard, delicate hyphal 

 threads extend through the ectoplasm to the surface of the body, where 

 they broaden and continue as extracellular threads. Basal branching is 

 common, and there may also be secondary branching. Infected amoebae 

 show a polar organization, with the fungi at the posterior end; this 

 polarity, Geitler concluded, is probably not called forth by the infec- 

 tion, but was present before. 



Filaments seen by Penard (1905c) on Amoeba proteus, the same as 

 those shown by Leidy on "Ouramoeba botulkauda," were, when of some 

 length, divided by constrictions into two or more equal parts. The 

 figure of a filament on A. vespertilio shows constrictions marking 

 short subdivisions. Dangeard (1910), who observed nuclei in the fila- 

 ments on Pelofnyxa vorax [Amoebophilus penardi), also figured con- 

 strictions demarcating long sections, which he considered to represent 

 budding. 



The incidence of these parasitic fungi on amoebae is sometimes high. 

 At one period Geitler found 95 percent of A. proteus infected; later the 

 incidence declined. Penard (1902) found the fungi on three out of five 

 A. nobilis, and Dangeard (1910) on a rather large number of Pelomyxa. 



A filamentous, cylindrical fungus, 0.75 |.i in diameter, was found 

 by the writer fairly frequently in certain material of Devescovina hawa'i- 

 ens'is from Neotermes connexus. A large part or all of the filament was 

 embedded in the cytoplasm, but characteristically a part projected beyond 

 the surface. The surface was penetrated at any point. 



Fungi which develop in the cytoplasm and then extend projections 

 beyond the surface were described by Penard (1912) in Amoeba terri- 

 cola and A. alba. These parasites, which he found usually fatal to the 

 amoebae, belonged, he thought, in or near the Saprolegniaceae. 



A fungus assigned to the Saprolegniales was found by Sand (1899) 

 infesting more than half the specimens of Acineta tuberosa collected 

 from the sea at Roscoflf. Developing within the cytoplasm, the parasite 

 soon destroyed the cell and formed isolated spheres in the empty lorica. 

 These developed into long tubes, wound in the lorica or projecting free. 



