Cretaceous sponges from the Campanian of Misburg and Höver
Cycloclema compressa is an ear- or funnel-shaped sponge with some habitual similarities to Rhagadinia rimosa and Phymaraphinia infundibuliformis, particularly the radiating furrows on the outer surface (See top figure).
However, on closer inspection, Cycloclema can easily be distinguished: On its upper side, the species has some peculiar tube-like, obliquely exiting exhalent channels, which form large ellipsoid pores, arranged in a radial pattern.
Another example of Cycloclema compressa, with a fairly long stem.
The tetracladine spicules of Cycloclema compressa are also very characteristic, with ring-like swellings around each arm near the center. One of the four arms is usually reduced to a round tubercle.