ABSTRACT
Nematocyst types of Cassiopea andromeda were investigated. Medusae samples were taken from Güllük Bay, Mugla, Turkey. Nematocyst samples from oral arms of C. andromeda were observed on light microscope and photographed. Birhopaloid and a-isorhiza nematocyst types were found in C. andromeda. Moreover, it was seen that nematocyst sizes increased with increasing the bell diameters of the individuals. Also, the venom of the species was isolated and injected intramuscularly to Cyprinus carpio juveniles. Signs of partial paralysis, raking, and immobilized fins were observed in the juveniles consequently. Death was observed for the fishes which were 3-4 g in the range of weight. This study is a preliminary work on nematocysts and venom of C. andromeda. Further studies on neurotoxic effects of nematocyst venoms of this species should follow.