CHAETOTAXY AND SURFACE-STRUCTURES OF THE MIRACIDIA OF ICHTHYOCOTYLURUS-ERRATICUS (RUDOLPHI, 1809), I-VARIEGATUS (CREPLIN, 1825) AND APATEMON-GRACILIS (SZIDAT, 1928) (DIGENEA, STRIGEIDAE)

Silver nitrate staining was used to investigate the number and arrange ment of argentophillic structures (epidermal plates, sensilla, excreto ry pores) of three species of strigeid miracidia, Ichthyocotylurus err aticus (Rudolphi, 1809), I. variegatus (Creplin, 1825) and Apatemon gr acilis (Szidat, 1928). The epidermal plates of all three species of mi racidia were arranged in four tiers according to the formula (6 + 9 4 + 3) = 22, while the number and distribution of sensilla were also f ound to be identical. Modifications to the nomenclature of Dimitrov et al. (1989) for miracidial chaetotaxy are proposed. Scanning electron microscopy (SEM) was also employed to examine the surface structures o f deciliated miracidia of Ichthyocotylurus spp., confirming the positi on and revealing the form of body sensilla.