Abstract
The Cleavage plane in animal cells and eggs is known to be determined by the position of the mitotic apparatus (cf. Wilson, 1925). A displacement of the mitotic apparatus by centrifugation (Harvey, 1935), mechanical deformation of eggs (Rappaport, 1960, 1961) or by microsurgical operation (Carlson, 1952; Waddington, 1952; Kawamura, 1960; Chambers & Chambers, 1961; Dan & Kuno Kojima, 1963) results in a corresponding change in the location of the cleavage furrow. This shows that the position of the cleavage furrow is determined by the mitotic apparatus of the cell.