Fig. 4

Photos of the test of S. oceana collected on DFS2 in the Panarea Volcanic Complex, taken under the binocular microscope: (a) detail of the needle-like spicule fragments along with a three-rayed spicule (triaene = t); (b) detail of the arrangement of the spicule fragments slightly twisting around the major axis of the stalk; (c) details of the test of the stalk with densely packed spicules and attached sand grain (s); (d) broken portions of the test showing the internal wall