128 



THE BIOLOGY OF STENTOR 



Morgan commented that if a portion is removed the remaining 

 parts seemed to reconstitute the normal ingestive structure, though 

 this was generally replaced later by a new one. In my experience 

 an isolated gullet can attain a neat opening on the surface and 

 attaches to the correct end of a remnant of the membranellar band, 

 while the severed oral pouch with its membranellar border also 

 does not remain as cut but coils sharply to form a pigmented 

 depression with the shape of the inside of an abalone (Fig. 33A). 



Fig, 33. Relating to reconstitution and formation in situ of 

 mouthparts. 



A. Gullet severed inside of stentor, isolated oral pouch widely 

 displaced, gullet opening destroyed by anterior incision. Gullet 

 finds neat opening to exterior and joins adoral end of adjacent 

 membranellar band, while oral pouch coils sharply as if attempt- 

 ing mouth formation. Regeneration follows. 



B. Two types of gross oral injury which are followed by 

 mending without regeneration: sectioning mouthparts but 

 leaving them close together, and thrusting an eyelash into the 



gullet and out through opposite side of the cell. 



C. Before regeneration, adoral end of the membranellar 

 band may produce a small pit, or a tight coiling (D). 



