Secondary rays end as small discs) and microdiscohexasters (smaller forms of mesodiscohexasters).

Atralia (spicules associated with the atrial cavity) are mainly hexactines, rarely with pentactines or diactines.

[2] Rossella species are abundant on the Antarctic shelf, where they may cover as much as half of the sea floor.

[3] A wide variety of invertebrate species also live within the sponge structure, including foraminiferans, polychaetes, amphipods, isopods, tanaids, copepods, ostracods, acari, pycnogonids, gastropods, bivalves, and nematodes.

[3] These typically represent a rapid evolution of a dominant (and endemic) group in a region, resulting in many similar species.