Marine invertebrates

Marine invertebrates are invertebrateanimals that live in marine habitats, and make up most of the macroscopic life in the oceans. It is a polyphyleticblanket term that contains all marine animals except the marine vertebrates, including the non-vertebrate members of the phylumChordata such as lancelets, sea squirts and salps. As the name suggests, marine invertebrates lack any mineralizedaxialendoskeleton, i.e. the vertebral column, and some have evolved a rigid shell, test or exoskeleton for protection and/or locomotion, while others rely on internal fluid pressure to support their bodies. Marine invertebrates have a large variety of body plans, and have been categorized into over 30 phyla.