These include bivalve molluscs, polychaete worms, barnacles, gastropod molluscs, other echinoderms and carrion. Invertebrate paleontology deals with fossils such as molluscs, arthropods, annelid worms and echinoderms. Eats mollusks, crustaceans, echinoderms and worms. Shellfish include various species of molluscs, crustaceans, and echinoderms. Permian marine deposits are rich in fossil mollusks, echinoderms, and brachiopods. Ammonotelic animals include protozoans, crustaceans, platyhelminths, cnidarians, poriferans, echinoderms, and other aquatic invertebrates. Many types of corals, brachiopods, molluscs, echinoderms, and other invertebrates had disappeared. Other groups include aquatic reptiles, amphibians, and miscellaneous invertebrates, such as echinoderms and jellyfish. An endoskeleton derived from the mesoderm is present in echinoderms, sponges and some cephalopods. Their diet can also include turtles, birds, dolphins, terrestrial mammals, crustaceans, and echinoderms. Marine life is especially rich in crinoids and other echinoderms. Such a skeleton is present in echinoderms and chordates. Amongst the echinoderms, the crinoids were the most numerous. Information about the stomach in echinoderms or molluscs can be found under the respective articles. Hemichordates form a sister phylum to the echinoderms.