Swimming Medusa (image) University of Vienna Share Print E-Mail Caption This is a swimming medusa of the hydrozoan jellyfish Clytia hemisphaerica. The contraction of circumferentially oriented striated muscles lead to the typical jet propulsion during jellyfish swimming. Credit Patrick Steinmetz Usage Restrictions Please note the Copyright Share Print E-Mail 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.