212 



THE BIOLOGY OF STENTOR 



Fig. 6o. Adjustments among formed ectoplasmic organelles. 



A. Regeneration primordium sector with intact mouthparts 

 grafted to stentor from which mouth was excised. Graft shifts 

 its alignment, anlage is resorbed and mouthparts join with 

 membranellar band to form a complete set of feeding organelles 



so that no subsequent regeneration occurred. 



B. Grafted patch with wide striping and section of mem- 

 branellar band (x). The peristomal remnant travels all the way 

 to the anterior end of the host and is incorporated into the host's 

 band, even with resorption of a part of that band to permit 



entrance. 



C. Small stentor, with mouth excised, grafted to another 

 whose mouthparts were cut in two. Mouthparts mend as 

 completely normal structure, separate membranellar ring moves 

 to anterior end of larger animal and is incorporated, no 



regeneration following. 



D. In parabiotic graft of two stentors the feeding organelles 

 fuse in spite of intervening striping and parts of both membra- 

 nellar bands are resorbed to make a single frontal field. 



