Black tunicate / Sea Squirt GALLERYPhallusia nigra
Sea Squirts are another name for the members of the class tunicate . While some tunicate s are "Threatened species", like this one, other species are exploding in population and causing problems. Sea Squirts are thought to be a precursor to the human heart! Read Article (external Link). these Black tunicate s are found in the mangroves, on wall faces, in between rocks and just about any where else and in water as shallow as a couple of feet. They are the largest tunicate of all the ones I've photographed snorkeling in St. John waters. The tallest siphon (incurrent) may be 2 inches tall.