Minchinia nelsoni n. sp. (Haplosporida, Haplosporidiidae): causative agent of the Delaware Bay oyster epizoötic.

Since 1957, oyster popuulations of the Middle Atlantic coast have been ravaged by a new sporozoan parasite that has been called "MSX." This parasite is identified as a new species of Minchinia that invades oysters through epithelial tissues of gill, palp, water tubes, and, occasionally, of the digestive tract. Multinucleate plasmodia are recognized in fresh and fixed preparations.