Abstract
Mitraspora cyprini was found in the diseased kidney or ureter or both of goldfish, most of which were collected seasonally from representative goldfish farms in Edogawa Ward, Tokyo. Histological observations of both healthy and diseased kidneys were made. Observations were also made of smeared and stained preparations and living specimens of M. cyprini.
The spore is oblong with slightly attenuated anterior end. Each of the two shell valves bears eight striae. It has eight caudal filaments, two polar capsules and a binucleate amoebula.
The trophozoites multiply in the renal tubules by the processes of plasmotomy and gemmation and infect the epithelial cells. The trophozoites are polysporous and the spore is monosporont.
Though this Mitraspora differs slightly in taxonomic features from the previous authors', the author identified it as M. cyprini.
Infection takes place through the mouth. The liberated binucleate amoebulae, penetrating the wall of the small intestine, reach the tubules through glomerules by blood. Intracellular and intraluminar life follow multiplication and sporogony in the tubules. The whole life cycle takes a year to complete.
