This rough scallop sponge (Myxilla incrustans) is the strangest one I’ve encountered so far, with very dramatic chimney like openings (oscula) across its surface. These chimney openings are where water exits the sponge after first having been gleaned of food particles. These sponges may start out small, but eventually cover the entire scallop’s shell surface. The rough scallop sponge has a range that includes Japan, as well as the Arctic to southern California.
