Figure 3.

Stylophora pistillata: (a) PLM image, (b) DIC image, (c) a component map, and (d) an average PEEM image overlaid with the component map, as described in Figure 2. (e, f) The regions boxed in panels c and d are magnified here to show amorphous particles where calicoblastic cells are expected. This region shows several scars left by desmocytes, the cells that bind the calicoblastic epithelium to the skeleton and form 3-μm-deep V-shaped scars, indicated by white arrows in panel d. Distinct particles are visible just outside the skeleton surface (e.g., cyan arrowhead in panel d, and three particles in panel f). These extraskeletal particles have both a greater percentage of amorphous pixels and a greater concentration of amorphous phases per pixel, compared to the skeleton surface or bulk (Tables S2 and S3). Extraskeletal particles are mostly amorphous within the calicoblastic epithelium, <2 μm outside the yellow line in panels d and f. Intraskeletal amorphous pixels in panel d extend ∼1 μm inside the yellow line. See Figure S3 for more images of this area.