Ok, I THINK that I have finally manged to find some forams in my marine tank. Not completely sure. Their tests, if that's what they are, do display some nice birefringent effects. In the 4th image you can see alternating blue and yellow zonation where the combined phase shifts from the test and the retarder in the scope (plus the final linear polarizer) filter out red or blue from the incident light. Taken through a BX-60 with appropriate lower nomarski prism/polarizer, UPlanApo 40/0.85 objective, U-DICT upper nomarski, Leitz VarioOrthomat eyepiece, 0.32X projection lens and D300. SB-800 flash in remote mode provided illumination.
The upper DIC prism was set to various retardation values to generate the effects seen, from "ordinary" DIC in the first image to the various other background and sample colors.
David
Last edited by discomorphella on Wed May 15, 2013 1:37 am, edited 2 times in total.
Molti grazie. The specimens were so small I never suspected that they could be worms. I was thinking they could be Ammodiscus....I have edited the post to reflect their true identity and my mistake