Difflugia lobostoma parasitism
When I was trying to identify some Difflugia specimens, I broke their shells by pressing the coverglass with a needle. With a little luck the nucleus comes out of the shell and can be observed. I use this as a key character for determination between D. gramen and D. lobostoma. When I broke a shell of what was apparently a test of D. lobostoma, because of the structure of the nucleus, a Rotifer came out of the shell together with a rotifer egg.
I have seen the following: a An active specimen of D. capreolata with in the test (between body and fundus) 4 eggs with a young rotifer. Eggs ca. 70 µm long and rotifer ca. 160 µm. b An empty test of D. capreolata filled with 13 specimens of a rotifer (Proales sp., one big specimen and 12 small ones). The big rotifer was ca. 210 µm long. c A test with 3 eggs and 2 active rotifers. In the test also a piece of protoplasma with nucleus. The plasma formed pseudopodia. d A test with 1 rotifer and 4 eggs, including protoplasma. e A test with 2 rotifers and 13 eggs (see drawing A above) and protoplasma with zoöchlorellae. Both rotifers had zoöchlorellae in their stomach.