| 1. Samples of benthic invertebrate fauna were collected in – a ditch, situated in a protected area in the peaty area near the Maarsseveense plassen (prov. Utrecht), – four ditches in the neighbourhood of Castricum (N-Holland), not far from the dune district, – two ditches with water of a high chloride-content on Texel (N- Holland). 2. The faunistic results, with the additional information of some physical and chemical data on the different sampling points, made it possible to draw some conclusions concerning – the importance of the factor salinity for a faunistically oriented typology of ditches, – the importance of the group Hydracarina for a classification of ditch-biocenoses, – the influence of artificial current, caused by the inlet of water, on the... |
