Formation and dynamics of female and male pronuclei in the fertilization of the eggs of Rana limnocharis.

Eggs of Rana limnocharis were inseminated with conspecific sperm and the formation and timing of the second polar body, the formation of female and male pronuclei, and their dynamic movements were observed. Sperm enter the egg at random locations around the second polar body, between 15 degrees and 60 degrees.