1050 PARASITES OF PROTOZOA 



parasites multiplying in this way alone would probably be cocci. That 

 may account for possible errors, not made in the above examples, but 

 probably involved in certain accounts of nuclear parasites, as discussed 

 below. 



When the parasite has reached a certain size, growth stops and 

 sporulation sets in. In Sphaerita amoebae the size when spores are 

 formed is very variable; sporangia are larger when only a few are pres- 

 ent in an amoeba (Mattes, 1924). The number of spores produced 

 is also variable in this species, ranging from less than a hundred to 

 several hundred. In sporulation the protoplasm simultaneously organizes 

 into membrane-confined bodies around each nucleus, and the spores 

 appear as spheroidal or ellipsoidal structures. The membrane of the 

 sporangium may remain very thin, so as to be scarcely recognizable, as 

 in Sphaerita in Amoeba alba, where groups of spores showed no trace 

 of an envelope (Penard, 1912). Sometimes it becomes more distinct 

 at sporulation; and in the unique case of Sphaerita from Nyctotherus 

 oralis, according to Sassuchin (1928a), it becomes 1 |j or more thick 

 (Fig.217C). 



The account by Sassuchin et al. (1930) and Sassuchin (1934) of 

 the parasite of Entamoeba citelli is not easy to understand. The parasites 

 are said to occur either in groups, varying considerably in size, which 

 resemble sporangia, but around which a membrane was never observed; 

 or arranged singly in the protoplasm. Though these parasites show a 

 spore-like character, the authors did not call them spores, nor did they 

 discuss multiplication. The description by Becker (1926) of Sphae- 

 rita endamoebae from Entamoeba citelli, to which Sassuchin did not 

 refer even in his later article, is in essential agreement with the usual con- 

 cept of the life cycle of Sphaerita. 



The parasite of Englena caudata (probably Sphaerita dangeardi) 

 may form as many as 500 spores (Mitchell, 1928). Sporangia of S. 

 endogena contain 100 or more (Dangeard, 1886a). Dogiel (1929) 

 found only from 30 to 40 spores in the "spore balls" of 5". diplodiniorum. 

 In Sphaerita of Monas vulgaris, nuclear divisions preceding spore forma- 

 tion proceed to stages 16, 32, or sometimes 64 (Alexeieff, 1929). Pinto 

 and Fonseca (1926) mentioned sporangia of only from 7 to 9 "individ- 

 uals" in S. ?ninor of Trichomonas vitali; Cunha and Muniz (1934) 

 found from 20 to 30 spores in S. chilomasticis. 



