Complex sentence: The large and ancient marine clade Patellogastropoda is a clade consisting entirely of limpets, and the common name "limpet" is often applied to the family Patellidae, and other families of limpets within that clade.
Split into simpler sentences: The large and ancient marine clade Patellogastropoda is a clade consisting entirely of limpets. The common name "limpet" is often applied to the family Patellidae, and other families of limpets within that clade.