MICRURGICAL EXPERIMENTS ON CYTOKINESIS IN STENTOR COERULEUS

Cutting and grafting experiments on the ciliate Stentor coeruleus during division stages indicated or demonstrated the following: (1) Unequal division after excision of one cell end showed that the location of the fission line usually remains predetermined but this line is not an indispensable constriction organelle. (2) The fission line is always smooth in spite of irregularities in the cell surface and it cannot extend across gaps. (3) A transequatorial piece of a divider can go on to divide anywhere on a divider in the same stage of division but its fission is not autonomous because it can be affected if the host cell is in a very different stage of division or is a non‐divider. (4) After removing half the presumptive or actual fission line or furrow a stentor can still divide along the line of healing. (5) Transverse cuts, though resembling a division line, do not serve for fission. These results suggest a morphogenetic hypothesis of cell division in Stentor. Copyright © 1968 Wiley‐Liss, Inc., A Wiley Company