Ink Sack (IMAGE) University of Texas at Austin Caption A fossilized mantle of a vampyropod, a relative to the vampire squid. The ink sacis the raised structure in the center, and muscles have a striated appearance. Credit Rowan Martindale/The University of Texas at Austin Jackson School of Geosciences. Usage Restrictions credit 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.