Adult Sea Urchins on Sea Floor (IMAGE) Smithsonian Tropical Research Institute Caption Adult sea urchins look like pin-cushions on the sea floor, while their microscopic offspring swim in the water column above. Credit Rachel Collin laboratory Usage Restrictions Please credit lab License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.