<em>Lymnaea stagnalis </em>and <em>Xenopus laevis</em> (IMAGE) Cell Press Caption Sinistral and dextral pond snails (Lymnaea stagnalis) and tadpoles (Xenopus laevis) are pictured. Sinistral snail is on left. Credit Photography by Esther de Roij and Gary McDowell, digital composition by Jeremy Guay, Peregrine Creative. Usage Restrictions Credit Required. 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.