Abstract

Corbicula fluminea, one of the 2 species in the family Corbiculidae living in the Lake Uiam, was used as an experimental material and the embryonic development and the structure of glochidia of this species were investigated. This freshwater mussels was oviparous, but some ovoviviparous: incubated their youngs in the inner-demibranchs or outer-demibranchs, however, chiefly used the inner-demibranchs as brood-pouch. The average time required from a fertilized egg to two-cell stage, veliger stage, and glochidium was 76 minutes, 3 hours, and 17 hours, respectively, The mean size of glochidium was <TEX>$168{\mu}m$</TEX> in shell height, <TEX>$195{\mu}m$</TEX> in shell lengh, <TEX>$114{\mu}m$</TEX> in hinge legth and the form of glochidium was D-type and had no hooks or hooklets for attaching to fish like Unioidae.