This paper reviews recent investigations on nuclear and cytoplasmic factors affecting the interautogamous interval. It is concluded that although its length is essentially determined by the macronucleus, cytoplasmic factors also play an important role in its regulation. Apart from immaturin, the authors summarize observations indicating the possible presence of an 'autogamous immaturity factor' and 'autogamy accelerating factor'.
M. Prajer, Department of Experimental Zoology, Institute of Systematics and Evolution of Animals, Polish Academy of Sciences, Slawkowska 17, 31-016 Krakow, Poland. E-mail: prajer@isez.pan.krakow.pl