This large sponge grows on rocky reef and takes on a massive form. Often consisting of a single lobe, it has a cluster of osculae at the top of the lobe, or otherwise in a specific area of the sponge. The rest of the surface of the sponge is covered in large nodules. It can vary in colour, but is usually dark grey to greenish brown and almost yellow. It is one of the easier sponges to identify, and the large nodules differentiate it from other similar species, such as Psammocinia. This sponge is a member of the boring sponges (family Clionaidae), and as such, bores into its soft stone substrate.
