Entobia
Introduction ''Entobia'' in a bivalve shell, Florida. '''''Entobia''''' is a trace fossil in a hard substrate (typically a shell, rock or hardground made of calcium carbonate) formed by sponges as a branching network of galleries, often with regular enlargements termed chambers. Apertural canals connect the outer surface of the substrate to the chambers and galleries so the sponge can channel water through its tissues for filter feeding (Bromley, 1970). The fossil ranges from the Devonian to the Recent (Taylor and Wilson, 2003; Tapanila, 2006).
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External links *  Image of ''Entobia cretacea'' as a cast showing canals and chambers in three dimensions''Entobia'' from the Prairie Bluff Chalk Formation (Maastrichtian, Upper Cretaceous) of Starkville, Mississippi. Preserved as a cast of the excavations.