I was assigned to run an aquatic ecology station during Resaca's grand opening, so had a bunch of pre-collected inverts, a couple of microscopes and other aids for viewing them, and a few relevant books. A few of these critters turned up when I slurped some aquatic plants and algae out of the resaca to study on deck C, where we were stationed. I "digiscoped" the photos using my Canon Elph and one of the microscopes. I recognized the critters because of one time at Duke, where I TA'd a biodiversity course, when Carolina Biological sent us a sample of some other freshwater critter species which was heavily contaminated by some sort of Pleid.