The nervous system of Procerodes littoralis (Maricola, Tricladida). An ultrastructural and immunoelectron microscopical study

The ultrastructure of the nervous system of a planarian, Procerodes littoralis, belonging to the taxon Maricola is described for the first time. The study has revealed the presence of two neuronal cell types and a glia-like cell. Immunogold labelling with antibodies to two native flatworm neuropeptides-neuropeptide F and GNFFRFamide-has been localised to one neuronal cell type and associated processes and synapses, thus indicating its peptidergic nature. The ultrastructural features are compared to those of other investigated turbellarian species. The number of features shared by species from the Proseriata, Lecitoepitheliata and Tricladida show that in respect of the nervous system these taxa form a closely related group. (C) 1997 The Royal Swedish Academy of Sciences. Published by Elsevier Science Ltd.