51�Թ�

The first formed polar body frequently divides when the o�cyte undergoes its second and final division, so that there are three polar bodies as well as the ovum resulting from the division of the o�cyte or progamete.

The general rule appears to be that the female pronucleus is without a centrosome, and that no centrosome appears in the female in the divisions by which the gamete arises from the progamete.

In most forms in which the formation of the gametes from the progamete has been accurately followed, and in which the progamete of both sexes divides twice in forming the gametes, the division of the nucleus presents certain peculiarities.