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;
Portuguese man o' war up on a beach may lead to the closure of the beach. Being a colonial siphonophore, the Portuguese man o' war is composed of three types of medusoids (gonophores, siphosomal nectophores, and vestigial siphosomal nectophores) and four types of polypoids (free gastrozooids, gastrozooids with tentacles, gonozooids, and gonopalpons), grouped into cormidia beneath the pneumatophore, a sail-shaped structure filled with gas. The pneumatophore develops from the planula, unlike the other polyps. This sail is bilaterally symmetrical, with the tentacles at one end. It is translucent, and is tinged blue, purple, pink, or mauve. It may be long and may extend as