Delayed gestation in the Potoroo Potorous tridactylus (Kerr)

Abstract

The histological changes in the corpus luteum and uteri of P. tridactylus throughout delayed gestation are described. Early in gestation there appears to be a unilateral stimulus of the uterus ipsilateral to the corpus luteum. Late in gestation there appears to be a foeto-placental stimulus of the pregnant uterus. Embryonic development is closely associated with the uterine changes. At about day 29 after removal of pouch young the foetus is born via the median vagina. A model is proposed to explain the apparently great discrepancy between the length of delayed and undelayed gestation in this species.