GREGARINA. 



95 



be no contractile vacuole and no nervous nor respiratory 



organs. 



The cuticular cap serves to fix the animal to the wall 



of the intestine in its young stages, but it is shed soon after 

 the attachment is lost. Conjugation takes 

 place but in a modified form. Two gregar- 



ines become closely opposed to each other but do not fuse. 



They together form a sphere which then becomes enveloped 



Reproductive. 



Fig. 31. — Life-History of Gregarina. 



I (After BuTSCHLi.) 



Protomerite^^ 



Deutomerite . /<'*?^.* 



Nucleus 

 Cortex 



o.> 



Duct. Spores. 



Cyst. 



Epithelial Cell. 



I, The adult individual. 2, The cyst containing spores. ' 3, A single spore. 



4, Two conjugating individuals. 5, Five stages in the intracellular 



parasite, from left to right. 



in a cyst. Under cover of this cyst the reproductive pro- 

 cess is effected, hence it is distinguished as a sporocyst from 

 the simply protective cyst (or hypnocyst) of Afnoeba, The 

 cyst is somewhat complex, for it has small tubular apertures 

 for the subsequent escape of the spores. 



Inside the sporocyst the two gregarines break up by 

 multiple fission into a great number of small fragments or 

 spores, each of which secretes around itself a hard case. 

 Sometimes the conjugates separate and a single Gregarina 

 encysts and divides into spores. 



