Oxygyrus keraudreni (IMAGE) Census of Marine Life Caption Zooplankton species captured during the latest Atlantic expedition of the Census of Marine Life (aboard NOAA ship Ronald H. Brown). Oxygyrus keraudreni. Unlike its relative the pteropods, that fly through the water like a bird, this heteropod uses its flatted foot like a paddle to push it through the water. Unlike most other pelagic snails the shell is made of cartilage. Credit Russ Hopcroft, University of Alaska Fairbanks, NOAA, Census of Marine Life, 2006 Usage Restrictions Credit: Russ Hopcroft, University of Alaska Fairbanks, NOAA, Census of Marine Life, 2006 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.