2l6 



THE BIOLOGY OF STENTOR 



but usually open on the surface, while the vacuoles are wholly 

 internal though they may break through the surface later. Both 

 are lined with apparently normal ectoplasmic structure: pigment 

 stripes alternating with ciliary rows, and contractility was 

 sometimes noticed in the tubes. 



These remarkable structures were first observed in masses of 

 stentors (Tartar, 1954). The tubes, at least, can occur in single 

 individuals. One day I isolated a very abnormal coeruleus which 

 was apparently the result of an incomplete fission, and on the next 

 day the cell was seen to be filled with elaborate internal tubules 

 (Fig. 62A). One tube opened where the mouth should have been 

 and was therefore like an exaggerated gullet. There seemed to be 

 other tubes with many convolutions which arose separately and 



Fig. 62. Interior tubes and vesicles in S. coeruleus. 

 A. Front and back views of case apparently from aborted 

 fission which developed complex system of multiple tubules, 

 blue-green in color because lined with ectoplasm. 



