Lophelia pertusa colony fragment GeoB12738-1 was sampled from a living colony at 34°59.98'N, 07°04.51' in 738 m water depth with the MARUM ROV CHEROKEE during Pelagia cruise 64PE284 in the Meknes mud vulcano area, Gulf of Cádiz. The colony fragment was scanned using a Toshiba Aquilion 64™ computer tomograph (CT) at the hospital Klinikum Bremen-Mitte, with an x-ray source voltage of 120 kV and a current of 600 mA. The CT image stacks have a resolution of 0.35 mm in the x and y directions and 0.5 mm resolution in the z direction (0.3 mm reconstruction unit). Images were reconstructed using Toshiba's patented helical cone beam reconstruction technique. Polyp-cavity (calice) segmentation was perfromed with the ZIB edition of the Amira software (Stalling et al., 2005; http://amira.zib.de) based on the new method describes in Schmitt et al. (submitted).