PARAMECIUM 61 



is the line of division? Can one speak of "parent" and 

 "offspring"? Stain the dividing animals with methyl green 

 and note what changes are taking place in the nucleus. 



(6) Conjugation. This is of less common occurrence 

 and depends in part upon the physiological condition of the 

 animals. Look for pairs of individuals which are joined 

 together by the buccal groove. This contact of the animals 

 is only temporary for they later separate; in the meantime, 

 however, portions of the nuclei have been exchanged. If 

 slides with stained specimens showing conjugation are at 

 hand examine them for the nuclear changes involved. Is 

 there any distinction of sex in these conjugating individuals? 



