Sea squirts attached on reef (IMAGE) Institute of Science and Technology Austria Caption Sea squirts attached on reef. The marine organism is a great model to study developmental processes of vertebrates. Credit © Shutterstock/ISTA Usage Restrictions Free to use when reporting about ISTA. 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.