A short resume is given of an extensive study of the formed elements of the cytoplasm in various Bryophyta, Pteridophyta, and Spermatophyta. In plant cells generally 4 different classes of cytoplasmic components have been found: (1) the osmiophilic platelets, which studies of sperm formation in mosses indicate to be the equivalent of the animal Golgi apparatus; (2) the plastidome, a group of bodies elongate or thread-like in meristem from which the typical plastids of more differentiated cells take their origin; (3) the pseudochondriome, a collection of vesicular granules showing in some cases a tendency to elongation, and indicated by their probable behavior in moss sperm formation to be equivalent to the chondriome of animal cells; (4) the vacuome, including the minute primordia in early meristem cells, the whole forming the plant vacuole system. Under normal circumstances, these 4 classes of materials are probably independent and self-perpetuating constituents of the cytoplasmic system. Study of sperm formation in mosses (Polytrichum spp.) indicates that the processes involved have an essential similarity to the same steps in animal spermatids, thus permitting the drawing of conclusions as to the homolo-gies existing between the cytoplasmic formed bodies of plant and animal cells.