corôÙreôÙsponôÙding values of ö¡, or the angle which determines
the point on the periphery where it is cut by the partition-wall, MP. Two limiting cases are to be noticed here: (1) at 90ô¯ (point A in diagram), because we are at present only {366} dealing with arcs no greater than a quadrant; and (2), the point (B) where the angle ö¡ comes to equal the angle öÝ, for after that point the construction becomes impossible, since an anticlinal bisecting partition-wall would be partly outside the cell. The only partition which, after the point, can possibly exist, is a periclinal one. This point, as