SUMMARYZygospores ofMucor hiemaliswere germinated and the products of such germinations analyzed for mating type reaction. All of the products of a single germination gave rise to colonies which were of the same mating type. In almost 90% of the germinations the cultures obtained reacted as (+) strains.Improved methods of zygospore isolation are described.A type of zygospore germination, referred to as a“mycelial germination”is reported and briefly described.