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HANDBOOK OF PROTOZOOLOGY 



the intestine of a fish. The body is leaf-like or ellipsoidal, and 

 covered uniformly by cilia of equal length. There is no cyto- 

 stome and the nutrition is parasitic. The number of nuclei 

 varies from two to several hundreds, and the nuclei are of one 

 type. Asexual reproduction is by binary fission. In a number 

 of species copulation of the gametes has been observed. Encyst- 

 ment is common. One family. 







Fig. 144 a-e. Protoopalina intestinalis. (After Metcalf). a, stained 

 trophozoite f X265); b-e, stages in anisogamy. 

 f, g. P. saturfialis. X400 (After Leger and Duboscq). g, cyst. 



Family Opalinidae Claus 



Genus Protoopalina Metcalf. The body cylindrical or 

 spindle-shaped, circular in cross-section. Two similar nuclei 



