Complex sentence: The anchialine pool snail, scientific name "Neritilia hawaiiensis", is a species living in brackish estuaries and in anchialine pools with an operculum, an aquatic gastropod mollusk in the family Neritiliidae.
Split into simpler sentences: The anchialine pool snail, scientific name "Neritilia hawaiiensis", is a species living in brackish estuaries and in anchialine pools. These snails have an operculum, and are aquatic gastropod mollusk in the family Neritiliidae.