History of invertebrate paleozoology and simpler sea-dwelling organisms. By far, invertebrate paleozoology is the easiest type of fossil collecting. "Unlike" the difficult-to-analyze and hard-to-interpret fossils of paleobotany (plants) and micropaleontology (microbes), and "unlike" the rarely found and poorly preserved skeletons of vertebrate paleontology, invertebrate fossils are usually both common and simple to identify. This is because many prehistoric invertebrates were hard-shelled mollusks, brachiopods, trilobites, bryozoans, crinoids or corals who were buried amid marine, sediment-preserving conditions; and therefore frequently fossilized. Stone-age people were without doubt the very first fossil collectors. Fossilized echinoderms have been found in Dunstable, Bedfordshire, central England, decorating a long-buried human skeleton;
Hawksbill sea turtle other jellyfish, and sea anemones. They also feed on the dangerous jellyfish-like hydrozoan, the Portuguese man o' war ("Physalia physalis"). Hawksbills close their unprotected eyes when they feed on these cnidarians. The man o' war's stinging cells cannot penetrate the turtles' armored heads. Hawksbills are highly resilient and resistant to their prey. Some of the sponges they eat, such as "Aaptos aaptos", "Chondrilla nucula", "Tethya actinia", "Spheciospongia vesparium", and "Suberites domuncula", are highly (often lethally) toxic to other organisms. In addition, hawksbills choose sponge species with significant numbers of siliceous spicules, such as "Ancorina", "Geodia" ("G. gibberosa"), "Ecionemia", and "Placospongia".