I collected a fresh sample from my favorite (ice covered!) pond and found this species for the first time. It can look different depending on where the microscope is focused. The "inside" looks very much like a diatom. Around the cell is a "coat" of scales that reminded me of certain scaled amoeba tests. There was a single flagellum up front (not seen in these photos) and at the rear, a "tail" of scales. Interesting specimen.
In the last shot of these three I tried to get a close look at the scale "coat", and as you can see from the scale bar, we're dealing with some pretty small structures. Two "focus selections" are given to give a sense of the construction.
, don't think I have ever ran across one of these. The cold weather undoubtedly will bring about some very interesting pond critters along with diatoms and various algae, since more sunlight is getting to the water now and the DO (dissolved oxygen) levels are coming up. Though most pond critters do not need a high oxygen content, they seem to be most prolific during the cooler or colder season. 
