The purpose of this posting is to illustrate the structural modification that is continually taking place inside this interesting testate ameoba. I think it might be Arcella vulgaris?
The four photos grouped below are of the same Arcella shot over a 3 minute period. In fact I took about a dozen pics (1 every 15ish seconds) and every one was completely different. The photos were focussed "through" the test - which from other pics that I took appeared to be a ribbed dome (you can see some of the ribbing near the outer edge of the animal). I was unable to identify the double nuclei with any certainty. I did wonder about the round organelle(ish) looking features at about 11 and 4 o'clock?
The two small, single celled critters seem to be inside the test (if that's possible?) or underneath the animal, as they disappeared when I pulled the focus up onto the top of the test. You would have expected them to move into sharper focus if they were above the test.
Bruce
