The mouth of a coral polyp (center): Symbiotic algae are labeled in red, pathogenic bacteria that enter through this region are labeled in blue. Disclaimer: AAAS and EurekAlert! are not ...

Indeed, if you take an india rubber bag, and place a number of strings around its mouth, you have a very good typical polyp. The polypi are not all microscopic, but some attain the size of the ...

Each polyp has a mouth surrounded by tentacles, usually arranged with six-fold symmetry. The polyps produce a hard outer skeleton made of calcium carbonate, each laying down a hexagon-shaped ...