LIGHT-MICROSCOPIC AND ELECTRON-MICROSCOPI C STUDIES ON THE SPOROGENESIS OF SPHAEROSPORA-MOLNARI IN THE GILL LAMELLAS OF THE COMMON CARP (CYPRINIUS-CARPIO)

The sporogenesis of Sphaerospora molnari in the gill lamellas of the c ommon carp was investigated by light- and electron microscopy. Whereas pseudoplasmodia were not identified, the development from one seconda ry cell containing two tertiary cells to the mature spore was pursued. Monosporic sporoblasts surrounded by an envelope cell were observed l ying isolated in the host tissue. Sporoblast generative cells differen tiated into two capsulogenic cells, two mononucleate sporoplasms and t wo valvogenic cells. In the course of valvogenesis the latter lost the ir cytoplasmatic vacuoles to form the electron dense valves of the mat ure spore. Via capsular primordia with external tubules polar capsules containing polar filaments developed in the capsulogenc cells. In con trast to valvogenic and capsulogenic cells, sporoplasms were not submi tted to structural changes.