THE ULTRASTRUCTURE OF THE TEGUMENT AND CLAMP ATTACHMENT ORGAN OF GOTOCOTYLA-BIV-AGINALIS (MONOGENEA, POLYOPISTHOCOTYLEA)

The tegument of Gotocotyla bivaginalis consists of a syncytium, perika rya and four kinds of secretory bodies, viz. electron-dense granules, moderately electron-dense vesicles, electronlucent vesicles and large multivesicular bodies occurring in the ratio of 83:50:40:1. Microvillu s-like structures, finger-like projections and a thin coat of glycocal yx occur on the tegument. In contrast, the syncytium of the clamp is r elatively thin and irregularly folded, containing only three kinds of secretory bodies, viz. electron-dense granules, a few moderately elect ron-dense granules and several large electronlucent vacuole-like struc tures in the ratio of 15:2:5. Exocytosis of the electron-dense and -lu cent vesicles is apparently prevalent both in the syncytium of the hap tor and general body surface. Tegumental damages induced by natural me chanical forces appear to occur in some regions of the syncytium of th e clamps/haptor. Sclerites of the clamp are electron-dense and they ar e interconnected by the basal lamina, tendon and radial muscle fibres. Interstitial space is absent between the sarcolemma of adjacent muscl e fibres of the clamp. Groups of neurons and non-myelinated nervous pr ocesses can be seen in the vicinity of the clamps. The axon is subdivi ded by invaginations of the neurolemma. Presumed non-ciliated mechano- receptors occur on the body surface.