Egg containing the embryo of a mud snail (Galba truncatula). The mud snail is a European freshwater pond snail which feeds on algae and fresh or decomposing vegetation. It lays clusters of 2 - 15 eggs on stones and submerged twigs. The adult snail is the vector of fascioliasis (infection with the liver fluke Fasciola hepatica) in humans and herbivorous mammals, and is the intermediate host for a number of other parasitic flukes. Footage filmed at Ridgeway Research, Gloucestershire, United Kingdom.