Abstract
The genusMonospora(=Monosporellarenamed) was founded by Metschnikoff in 1884 to designate a parasitic fungus which he discovered inDaphnia magna. This monocellular fungus, of which he described only one species,Monospora bicuspidata, lives free in the body cavity of its host, where it multiplies actively by budding in a yeast-like manner (Fig. I, 1, 2, 3).