Pleuronectidae and they sink to the bottom. They are found on the bottoms of oceans around the world, with some species, such as the Atlantic halibut, "Hippoglossus hippoglossus", being found down to . The smaller species eat sea-floor invertebrates such as polychaetes and crustaceans, but the larger righteye flounders, such as "H. hippoglossus", which grows up to in length, feed on other fishes and cephalopods, as well. They include many important commercially fished species, including not only the various fish called flounders, but also the European plaice, the halibuts, the lemon sole, the common dab, the Pacific Dover sole, and the
Flat pebblesnail Flat pebblesnail The flat pebblesnail ("Lepyrium showalteri") is a species of freshwater snail, an aquatic gastropod mollusk in the family Lithoglyphidae. This species is endemic to the United States. This snail has been listed as endangered on the United States Fish and Wildlife Service list of endangered species since October 28, 1998. "Lepyrium showalteri" is the only species in the genus Lepyrium. "Lepyrium showalteri" is the type species of the genus "Lepyrium". Lepyriidae is a synonym of Lithoglyphinae. The flat pebblesnail is a small snail in the family Lithoglyphidae; however, the species has a large and distinctive-looking shell. This snail's