10 



MORPHOGENESIS IN CILIATES 



reduced to a thin peripheral layer containing the macro- 

 and the micronucleus. When the fully grown ciliate leaves 

 the molted exoskeleton, expansions of the cytoplasm divide 

 the accumulated food. 



Phoront: Phoretic metamorphosis 



Tomite 



Young 

 trophont 



Fig. 2. GymnGdinioides inkystans: life cycle. 



The single enormous ingested lump is then reduced to 

 ellipsoidal platelets. These reserves are consumed during 

 the phoretic phase, which may last some months, until the 

 ecdysis of the host takes place. When the reserves are di- 

 gested, they first turn pink, owing to the separation of the 

 astacin from the protein, and finally astacin is precipitated 

 as small red granules. It is worth mentioning that reserves 



