A NEW TYPE OF SENSORY ENDINGS IN THE SUCKERS OF CESTODES

Electron microscope studies of the nerve system of the suckers in three species of cestodes of the family Hymenolepididae, Gastrotaenia dogieli (Gynezinskaja, 1944), Diorchis stefanskii Czaplinskii, 1956 and Sobolevicanthus spasskii Kornyushin, 1969, have revealed a new type of sensory endings unusual for this class of plathyhelminths. The sensory endings are characterized by subtegumental location, elongated ovoid shape, the presence of compact central body formed by differently oriented fibrils, thin-fibrillary bundles between the central body and numerous supporting rings with cross-striation in the base and by the absence of apparent desmosomal links between membranes of the ending and the tegument. Presumably these endings in species localized in the intestine provide for the regulation of the adhesion of suckers to the substrate, while in the reduced suckers of G. dogieli they provide for the motion of the cestode under the cuticle of the stomach.