Figure 5. Vesicles with silica-like granules within sponge cells. A in Recycling resources: silica of diatom frustules as a source for spicule building in Antarctic siliceous demosponges

Figure 5. Vesicles with silica-like granules within sponge cells. A, an amoeboid sponge cell (spc) in P. areolatus showing a cytoplasm packed with vesicles and an ingested diatom (di) within a large digestive vesicle. Note that three different granule types were identified by microanalysis in the section of this species: silica granules (si), and lead granules (Pb). B–C, highly vesiculated, amoeboid sponge cell in He. pilosus. Note the silica-like granules (si) first present within vesicles and later incorporated within the cytoplasm. D, amoeboid sponge cell in P. areolatus showing an ingested diatom (di) and silica-like granules (si).