The Sarcodina 221 



Fig, 5. 14. A-C. Labyrinthula zopfi Valkanov (individual organisms reach 

 8/i in length): portion of Hving network (A); two organisms stained (B); 

 encysted stage, from hving (C); schematic (after V.). D, E. Labyrinthula 

 macrocystis Cienkowski: vegetative network (D), x380 approx.; single organism, 

 stained, showing nucleus and vacuole (E), x2700 approx. (after Young). 



organisms within one membrane has been described in Labyrinthula 

 zopfi (Fig. 5. 14, C), and in L. macrocystis, a membrane may be formed 

 around a pseudoplasmodium composed of 5-100 organisms (162). 



The family includes Labyrinthula Cienkowski (145, 162), reported from eel grass and 

 certain marine algae (Cladophora, Chaetomorpha); and Labyrinthomyxa Duboscq (35), 

 reported from Laniinaria. Labyrinthula macrocystis has been found associated with a 

 fungal disease of eel grass (120, 162), and it is possible that the organisms, by attack- 

 ing the plant cells, contribute to the spread of infection. 



Family 2. Pseudosporidae. These organisms invade filamentous algae 

 and Volvocidae. The parasitic stages are amoeboid. Either flagellate or 

 amoeboid "swarm-cells" may be produced, depending apparently upon 

 the species. The best known genus is Pseiidospora Cienkowski (127, 134, 

 135; Fig. 5. 15). Several other genera- — Protomonas Cienkowski, Apheli- 

 dium Scherffel, Amoeboaphelidiujn Scherffel, Aphelidiopsis Scherffel, 

 Pseudosporopsis Scherffel, Barbetia Dangeard — appear to be related to 

 Pseudospora and presumably belong to the same family (134). 



A fairly complex life-cycle has been described for Pseudospora parasi- 

 tica (135). Growth of the young amoeboid stage into a mature form may 

 be followed by formation of a "zoocyst," or reproductive cyst (Fig. 5. 15, 

 A-D). According to Schussnig (135), gametes eventually are produced 



