First reported occurrence of Thelohanellus oculileucisci (Trojan, 1909) (Myxosporidia) and Leuciscus leuciscus (L.) and L-idus (L.) in Poland

A myxospridian, Thelohanellus oculileucisci (Trojan, 1909) was found in the vitreous body of an eye of a dace, Leuciscus leuciscus (L.) from the river Bug near Kamienczyk, and Leuciscus idus from the river Vistula near Warsza wa. The vegetative forms - several oval to round cysts, 0.4-0.5 mm in diame ter, contained numerous, pear-shaped spores with one polar capsule at the n arrower end. The parasite has not been noted until now in fish in Poland.