222 



HANDBOOK OF PROTOZOOLOGY 



The number of nuclei in each varies from three to a large num- 

 ber. During the encystment, the chromatin bodies of the 

 trophozoite become collected in several masses which then dis- 

 integrate and each chromatin grain becomes the endosome of 

 the newly formed nucleus. Sooner or later, the cyst contents 

 divide into several (four to eleven) multinucleate bodies and 

 the whole increases in size. Finally the cyst membrane dis- 

 integrates and the multinucleate bodies become set free. The 



Schizamoeba salmonis. X800 (After Davis).' 



Hydramoeba hydroxena. (After Reynolds and Looper). c, a 



heavily attacked Hydra oligactis which lost its tentacles 



(X70); d, section of an infected hydra showing a trophozoite 



feeding on ectodermal cells (X350). 



Paramoeba pigmentifera with its nucleus in the center. X600. 



(After Janicki). 



amoeba is said to occur in the mucous covering of the stomach 

 of the salmonoid fish and the cysts occur in both stomach and 

 intestine. Aside from the loss of certain amount of food avail- 

 able to the host fish, no pathogenic effect of the amoeba upon 

 the host fish was noted by the discoverer. 



Genus Hydramoeba Renolds and Looper. Ectoparasitic on 

 Hydra. The nucleus has the following characteristics in 

 stained condition : There is a large central endosome composed 

 of a centrosome (?) and chromatin granules are embedded in an 

 achromatic mass. Fine achromatic strands radiate frorn the 

 endosome to the membrane. In the nuclear sap zone, there is 

 a ring composed of numerous rod-shaped chromatin bodies 

 arranged regularly. The cytoplasm contains one or more 



