I've had the same type of "seeds" and posted about it in another forum. I was told by someone that it is Dog Tapeworm eggs. Dog Tapeworm is smaller than regular tapeworm. The eggs resemble pumpkin seeds or cucumber seeds.
To prevent re-infection, watch when you walk barefoot in grass or even your carpet if you have housepets that go outside. You dont even have to own a pet to get it--as it is carried by infected fleas. All you have to do is walk around with flip flops or barefoot in the grass- and get bit by an infected flea on your ankle-- then Viola!!-- the parasite larvea enters your bloodstream.