Morphological studies on some Difflugiidae from Yugoslavia (Rhizopoda, Protozoa) Colin G. Ogden Department of Zoology, British Museum (Natural History), Cromwell Road, London SW7 5BD Andjelija Zivkovic Institute for Biological Research, University of Belgrade, 29, Novembra 142, 11000 Belgrade, Yugoslavia Contents Introduction 341 Materials and methods 341 Systematic descriptions 342 Difflugia 342 Cucurbitella 369 Pontigulasia 369 Summary 373 References 374 Introduction Recent studies (Ogden, 1979, 19800, b, 1983; Ogden & Fairman, 1979) on the shell morphology of specimens belonging to the family Difflugiidae, have shown that detailed examination of these structures aid identification at the species level. It is now possible using the scanning electron microscope to demonstrate differences in shell structure and to examine more easily the type and arrangement of materials used in these complex con-structions. Earlier workers were handicapped in similar examinations by the limited resolution of reflective optical microscopy. This made comparisons of shell structure difficult due to the different densities of the shell ranging from opaque to transparent, and sometimes the shape made a complete survey impracticable, ovoid or circular shells being particularly awkward. The present work is based on specimens collected in Serbia, Yugoslavia, from an area of peat bogs located on the high plateau at 1200 m, now submerged by the artificial lake 'Vlasina', which was formed by damming the river Vlasina and flooding a depression. A limnological study of this lake by Milovanovic & Zivkovic (1956) gives information relating to the chemical and biological conditions during the initial formation of this feature. There are several reasons for our interest in the Difflugiidae of Yugoslavia, no previous records of testate amoebae are available for this region, there appears to be a similarity of this fauna with that reported from Africa by Gauthier-Lievre & Thomas (1958) and specimens of the so-called 'cosmopolitan' species are available for comparison with those already described from the British Isles. Furthermore, the presence of several compressed species of Difflugia is unusual, as these forms appear to be rare. Materials and methods Samples were collected in September, 1947 from a pond 'Godzina bistrica' located at the Bull. Br. A/MS. nat. Hist. (Zool.) 44(6) : 34 1-375 Issued 30 June 1 983
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