b c d e of the open oceans with more constant living conditions [181, lorica-splitting would seem to be less adaptive and is, therefore, not to be expected. In contrast, the coastal waters and estuaries of temperate latitudes can be characterized as strongly seasonally pulsed systems favoring opportunistic species like rotifers which are abundantly represented here [18]. Therefore, loricasplitting may be of selective advantage for neritic loricated ciliates, too. Descriptions of Kofoid ([2], p. 9) and Hofker ([8], p. 336) seem to imply observations of splitting activities which were unrecognized by the authors, of Tintinnopsis, the leading species-rich genus of this environment. This adds support to the suggestion that loricasplitting is also to be expected in these neritic species. Apparently, loricasplitting may contribute to the understanding of the ecology of Tintinnina. I thank Prof. J. Overbeck for his critical reading of the manuscript and Prof. W. Lampert, Prof. B. Zeitzschel and Dr. R. W. Sterner for discussion. I would also like to express my thanks to M. Wulf for advice by taking micrographs and to B. Albrecht and L. Tolkmit for assistance in their development and printing. This work was supported by grants from the Max-Planck-Society.