Hydractinia anatomy (IMAGE) NIH/National Human Genome Research Institute Caption Hydractinia's regeneration driving stem cells are stored in the lower trunk of the animal's body, far from the mouth. Credit Darryl Leja, National Human Genome Research Institute (NHGRI) Usage Restrictions Credit must be given to the creator. License CC BY 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.