Studies on the Division Rhythm of Chilodonella steini ( Blochmann, 1895) (Cyrtophorida)

Cultures kept in continuous white light were found to exhibit maximum increase in the number of cells. It was also found that cultures in the exponential growth phase are characterized by division rhythm when kept under the LD 12: 12 illumination programme, this rhythm being manifested in mass divisions at intervals of about every 24 h. White light was shown to be responsible for creation of the division rhythm and was also found to induce shortening of cell generation times, while darkness prolongs them. This phenomenon actuates the mechanism causing formation of division rhythm. It was found in addition that this rhythm is not of endogenic origin.