A new haplosporidian parasite, Coelosporidium schmackeriae from the body cavity of a marine copepodSchmackeria serricaudata

1. The morphology and life-history of a new haplosporidian parasite,Coelosporidium schmackeriae, from the body cavity of the copepod Schmackeria serricaudata is described. 2. The earliest stage observed was an amoebula which developed into multinucleate plasmodia. 3. The plasmodia may undergo a process of asexual multiplication or plasmotomy and this may be repeated. 4. Spore formation took place inside the plasmodia by the fragmentation of the cytoplasm into uninucleate bodies and these bodies ultimately developed into uninucelate simple spores enclosed in a common cyst. 5. Cysts are ovoid measuring 25.0μ in diameter and enclose 70-80 spores. The spore is ovoid measuring 3.0μ × 27sd5μ and provided with a rigid double envelope. Neither an operculum nor a bivalve nature of the spore was noticed. 6. The systematic position of the parasite is discussed