Hello. I found this species and I don't know what it is. I can see it the first time. It is quite small. I've done cropping additionally to give it bigger.
Polarized light
Lumipan - CZJ microscope
40 X Olympus S planachromat
2,5 X NFK
your image shows the amoeba Mayorella penardi parasitized by the fungus Amoebophilus simplex. I'm quite sure. You can recognize the round anchor-cell of the fungus located in the amoeba, the so called haustorium.
Thank you all for comments. Bernd and Martin, thank you very much for your help in ID. The your link Berndt is very useful, thank you. Now I know everything