On the totipotency of dedifferentiated cells originated from copulatory apparatus in the planarian

Following decapitation of Dugesia japonica ryukyuensis , and subsequent repeated removal of regenerating head-blastema, the copulatory apparatus degenerated after about 40-60 days. In this case, the copulatory apparatus disintegrated into cell clusters, which further divided into separate neoblast-like cells which finally transformed into ordinary parenchymal cells. When the head of worms with degenerated copulatory apparatus was regenerated after discontinuing the excision of the head blastema, a new copulatory apparatus was redifferentiated from the dedifferentiated cells.