See here for more details about where I found these samples:
http://www.microbehunter.com/microscopy ... f=6&t=3783
40X, Polarized light. 23 images in stack.
I am NOT sure about the identification, but it looks like Difflugia Acuminata.
Testate amoebae build a test or shell from material they find. Some of them form tests by gluing together organic or mineral particles (sand grains, diatom shells) from their surrounding environment.

