The purpose of this study was to investigate in the rabbit, the possibility of a relationship between fetal movement and the development of ossification. Fetal movements were investigated in a number of ways. After maternal cervical dislocation, movements were studied for as long as the fetuses responded to stimulation (except at ages after day 25 when 45 minutes was considered sufficient) after being exposed by hysterotomy. Movements both in and out of the amniotic sac were recorded by cine-photography. Two types of movements were studied: spontaneous and reflex (after surface stimulation). At least two litters were studied for each day of gestation from day 14 to day 30.