Studies on the Epidermis of Temnocephala. V. Further Observations on the Ultrastructure of the Epidermis of Temnocephala Novae-Zealandiae, Including Notes on the Glycocalyx.

Abstract

Additional information on the fine structure of the epidermis of Temnocephala novae-zealandiae is presented, including a description of modes of discharge of secretion at the epidermal surface. A thin, homogeneous coat or glycocalyx is applied to the apical plasmalemma. Delicate filaments of the coating material extend between microvilli. On the tentacular surfaces filamentous extensions of the glycocalyx penetrate the extraneous film of rhabdite origin. The glycocalyx materials are evidently formed as Golgi-organized epidermal secretory products; they are transported to the apical and basal plasmalemmata by clear vesicles or (more probably) microchannels. The system of microchannels is extensively developed in the ventral epithelium of the disc. Dumbbell-shaped dense bodies are scattered through the epidermis; many are closely applied to the clear vesicles or microchannels. The temnocephalid epidermis is, therefore, characterized by a fringe of microvilli with associated filamentous extensions of the glycocalyx, together with a system of microchannels of vesicles and associated dense bodies. These features are probably functionally related to the stability of extraneous films derived from parenchymal gland secretions, and their adhesion to the epidermal surface. [AS]