“…The ultrastructure of secretory ependymal cells constituting the subcommissural organ (SCO) which is situated on the roof of the third cerebral ventricle below the posterior commissure has recently been studied in fishes (AFZELIUS and OLSSON, 1957;MURAKAMI and TANIZAKI, 1966;STERBA, MULLER and NAUMANN, 1967;STANKA, 1967;ALTNER, 1968), amphibians (MURAKAMI and TANIZAKI, 1963;ALTNER, 1968), reptiles (MURAKAMI, 1959;MURAKAMI, KUSABA and YAMAKAWA, 1962) and mammals (ANDERSON, 1961;LIN and DUNCAN, 1961;WETZSTEIN, SCHWINK and STANKA, 1963;NAUMANN and VOLFE, 1963;LAATSCH, 1964;STANKA, WETZSTEIN and SCHWINK, 1964;ISOMAKI, KIVALO and TALANTI, 1965;HERRINGER, SCHWINK and WETZSTEIN, 1967;VIGH et al, 1967;BARLOW, AGOSTINO and CANCILLA, 1967;PAPACHARALAMPOUS, SCHWINK and WETZSTEIN, 1968;IMAIZUMI, 1968).…”