Schizoplasmodium, a Mycetozoan Genus Intermediate Between Cavostelium and Protostelium; a New Order of Mycetozoa

SYNOPSIS. Two new species of the simple mycetozoan genus Schizoplasmodium—S. ovatum and S. gracile—are described, the former having ovate spores and the latter spherical ones. All stages of the life cycle are multinucleate. At sporulation the holozoic plasmodium segments into prespore cells which develop directly into long‐stalked, single‐spored sporocarps. Sexual reproduction was not observed. A new order—the PROTOSTELIDA—is proposed for this and related genera, which are believed to comprise a phylogenetically linked series, beginning with the amoebo‐flagellate genus Cavostelium and evolving through Schizoplasmodium to Protostelium. The two families Cavostelidae (Cavostelium) and Protostelidae (Schizoplasmodium, Protostelium) are recognized.