Some pictures of the flatworms. The animals were transferred to a small plastic container and photos were taken with a macro lens. It was a bit harder than I thought it would be to get decent pics, but these are probably the best I could hope for with the equipment I have.
Incidentally, its not really clear what I should feed them. In some of the old literature with Dugesia tigrina, the authors use small cubes of liver. In the 60's, that probably wasn't hard to find, but few supermarkets stock liver these days. Liverwurst is not a substitute, apparently, but I will try some chicken meat soon. I've also tried dried bloodworms, which some of them have gone for, but its not entirely clear if they are feeding or just clinging on to them. The problem is that these are predators (Dendrocoelum in particular) and only occasionally scavengers, so I imagine simply wiggling a dead bloodworm in front of them isn't going to provoke much of a response.
(Note the eyes - Dugesia has large eyes that look 'cross-eyed' - the white bit is many retinal cells, the dark patch a few pigment cells. Dendrocoelum has just two dark dots composed of two retinal cells and a pigment cell.)