MONOCYSTIS 



127 



repeated fission into eight sickle-shaped sporozoites. There 

 are thus two generations of spores 1 in the life-history 



Fig. 77. — The life-history of Monocystis.— Aitex Biitschli. 



1. Young individual (c) lying within a sperm mother cell of an earthworm. 



2. Association of two individuals within a cyst, ready to form gametes. 



3. Numerous spore-cases (sp.c, pseudonavicellse) within a cyst. 



4. A spore-case with eight spores (sp.) and a residual core (r&.). 



Fig. 78. — Part of a cyst of Monocystis agilis showing the two kinds of 

 gametes and the residual protoplasm of one of the parents. — After 

 Hoffmann. 



of Monocystis. No further development takes place 

 until the pseudonavicellse get free from the worm, which 

 they generally do by the destruction of the latter. 2 

 Probably this takes place by its being eaten by a bird. 



1 A spore is a small reproductive body formed by multiple or re- 

 peated fission. It may or may not be a gamete. If it be enclosed 

 in a case it is known as a chlamydospore (e.g. pseudonavicellse), 

 if it be naked as a. gymnospore (e.g. spores of Amceba). Amoeboid 

 spores are known as amabula or pseudopodiospores, flagellate spores 

 as flagellalce or flagellispores, ciliate spores (p. 159) as ciliospores. 



* The details of the transference of the spores of Monocystis are very 

 imperfectly known. They can pass from one worm to another during 

 coition, but it is believed that this is not the usual method, if indeed 

 it be effective at all. 



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