The fine structure of the pore cells in connective tissue in the kidney of Achatina achatina and the skin of the slug Arion hortensis is described and evidence is presented which shows that these cells, in the latter species, are involved in the synthesis of the respiratory blood pigment, haemocyanin. The involvement of these cells in phagocytosis of colloidal particles, was demonstrated following introduction of ferritin and colloidal gold into the blood. The extracellular coat which surrounds the cells is permeable to ferritin, but is impermeable to colloidal gold. Following penetration of the extracellular coat the ferritin enters the sub-surface cisternae and is taken into the cells where it crystallises within membrane-bound vesicles.

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Intra-specific variability of root biomass production (RP) of six rooted macrophytes, i.e. Juncus effusus, Phragmites australis, Schoenoplectus lacustris, Typha latifolia, Phalaris arundinacea, and Iris pseudacorus grown from clones, in response to Cu exposure was investigated. Root biomass production varied widely for all these macrophytes in control conditions (0.08 μM) according to the sampling site. Root biomass production of T. latifolia and I. pseudacorus in the 2.5-25 μM Cu range depended on the sampling location but not on the Cu dose in the growth medium. For P. australis, J. effusus, S. lacustris, and P. arundinacea, an intra-specific variability of RP depending on both the sampling location and the Cu-dose was evidenced. This intra-specific variability of RP depending on the sampling location and of Cu-tolerance for these last four species suggests that Cu constitutive tolerance for all rooted macrophytes is not a species-wide trait but it exhibits variability for some species.

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Aestivating Otala lactea have been shown to reduce the rate of evaporative water loss from the cells of the mantle-collar epithelium to a level comparable to that of an insect. X-ray microanalyses of ultrathin frozen sections from aestivating and non-aestivating snails have shown gradients of chloride and potassium ions in the apical microvillus region of the regulating mantle collar epithelium. The greatest difference in osmotic concentration occurs in the apical 2 micron of the cell. There appears to be a barrier at that level that prevents water being mobilised from the underlying tissues. Methods of presenting data generated by X-ray microanalysis are also discussed.