The storage of glycogen in the body of 2 representatives in Ceylon of the group Temnocephaloidea is described. Glycogen is stored in almost all the organs of the animals. It is absent or found in negligible quantities in the outer layer of the body epithelium, in the diagonal muscles and in the epithelial lining of the reproductive ducts. Glycogen is found in the nervous systems of both animals. It is present in the excretory system of Caridinicola but not in Monodiscus. Monodiscus stores a relatively larger quantity of glycogen than does Caridinicola, which is a larger worm living together with the former on fresh-water prawns.