Some Observations on Dictyocotyle coeliaca Nybelin, 1941 (Monogenea)

Abstract

1. Heavy infestations of the coelom-dwelling trematode, Dictyocotyle coeliaca, in rays are reported.2. Of seven species of skates and rays examined, 16 of 55 specimens of R. naevtis and 81 of 78 specimens of R. naevus and 31 of 73 specimems of R. radiata were infested.3 The spindle-shaped, three-sided operculate eggs are described and possible modes of exit from the male and female hosts are discussed.4. A number of immature stages have been found and descriptions are given. Unlike the adults, the opisthaptor projects prominently beyond the posterior margin of the body, but the number and arrangement of the loculi appears to be the same.5. The systematic position of the trematode is discussed.