Light and electron microscopical study on sarcocysts from muscles of the rhesus monkey (Macaca mulatta), Baboon (Papio cynocephalus) and Tamarin (Saguinus(=Oedipomidas) oedipus).

Sarcocystis cysts from muscles of monkeys (baboon, tamarin and rhesus monkey) were studied by means of light and electron microscopy. The differences in the morphology of the cyst wall and parasites clearly indicate that the three monkey species examined were each parasitized by at least a specific Sarcocystis species being not identical with S. nesbitti or S. kortei. The large numbers of cysts found within the muscle fibres point out the important role that have these monkeys as intermediate hosts in the life cycle of Sarcocystis species, where the final hosts are still unknown.