Definition: The term "Neurochaetidae" refers to a group of animals that belong to the class Neurochordata, which is divided into three main families: Cephalochelidea (such as clams and oysters), Planktochoela (such as brachiopods), and Nectarchi (such as annelids). These groups share a common ancestor with chordates, the class of vertebrates that includes humans, animals, and plants.