262 



THE BIOLOGY OF STENTOR 



normal animals (Fig. 72). The dwarfs had tiny, proportionate 

 feeding organelles and the number of lateral stripes was about 

 half the normal, indicating the morphological adaptation to decrease 

 in size. Johnson had found that such dwarfs undergo no irrever- 

 sible changes and are capable of complete recovery, growing and 

 dividing when later fed. I demonstrated that fragments of these 

 tiny stentors were capable of normal oral regeneration. 



Fig. 72. Largest S. coeruleus compared to smallest individual 

 in starvation culture. The larger had a contracted diameter of 

 376 ju., 18 macronuclear nodes, and c. no pigment stripes. The 

 smaller : 94 /x, 5 nodes, and c. 56 stripes. Note that membranelles, 

 colored stripes, and nodes are not proportionately smaller in the 

 tiny stentor. 



As expected, the fat and carbohydrate reserves (further discussed 

 in the following section) are exhausted during periods of starvation 

 (Zhinkin, 1930). According to Weisz (1949a) their utiHzation is so 

 rapid that the endoplasm is cleared of these reserves within a day. 

 My impression is that at least the carbohydrate stores, which are 

 clearly visible as white granules in dark-field illumination are 

 exhausted much more slowly. Moreover, when survival of anterior 

 halves with little if any such reserves was compared with that of 

 posterior halves bearing abundant reserves no conspicuous 

 advantage from the stored material could be demonstrated. This 

 may have been due to the abnormal conditions apparently involved 

 in isolating animals into small drops on slides, for some specimens 



