A caudofoveate mollusc ( Falcidens sp ). Stained with osmium tetroxide and embedded in Spurr's resin for electron microscopy, scanned in resin block. Volume rendering (left) of a low-resolution scan, showing the anterior-most 1.4 mm of the animal. Cutaway volume rendering (center) and a single reconstructed section (right) of a higher resolution scan of the same block, showing the midgut region. This volume image was processed with a median filter (3 × 3 kernel). Scale bar = 100 μm. Voxel size 3.2 μm (left), 1.6 μm (center and right). Sample prepared and provided by Emanuel Redl, Univ. Vienna.