LIFE CYCLE OF NASSULA ORNATA AND N. ELEGANS. 243 



2. The well nourished phase, known as Nassula ornata, does 

 not encyst. Lack of food, first, converts Nassula ornata into 

 Nassula elegans, and, in time, drives the forms as Nassula elegans 

 into encystment. 



^Sj-^inary fission occurs more frequently in the poorly fed 

 forms (Nassula elegans) than in the well-nourished forms (Nassula 

 ornata} . 



4. There is but one nucleus in this ciliate, there being no 

 differentiation of the nuclear complex into micro- and macro- 

 nuclei. 



5. Conjugation involving this single nucleus takes place in 

 stocks that have aged. 



BIBLIOGRAPHY. 



1. Calkins, G. N. 



'26 Biology of the Protozoa. 



2. Cohn, R. S. 



'53 from Pritchard, A. "Infusoria," 1861. 



3. Eyferth, B. 



'oo Einfachste Lebensformen. 



4. Pritchard, A. 



'61 "Infusoria." 



