TEST OF FRESH WATER DIFFLUGIA SPECIES FROM SWANAGE BAY
Test in Simple reflected light
Test in crossed Polars with Victorian selenite plate
(N.B.Another test)Polar with cossed polars no plate
Quite often one change leads to a complete change of direction. I have been aware of the deposition of Fresh Water tests of testate amoeba in Swanage bay for several years but have rather overlooked them as an object of interest.
After several years of Dry mounting I have moved over to aspects of Mounting in Canada Balsam. and this has enabled photography using traditional methods such as Bright field, Dark field, and photography of arenaceous tests of foraminifera in polarised light.
More recently I have tried polarised light not only at full extinction of direct light but also when using various Victorian selenite plates. These effects are rather unnatural looking and much less sharp but never the less they are quite compelling. I include my first effort as the coloured image above. The less colourful one below is a test from several years ago shown for comparison.
The diversity comes from the external protective layer of particles bonded onto the internal bag of equally protective chitinous material.They are of various thickness each distinguished with its own colour dependant upon its structure and thickness.