Heterochone calyx
Schrammen 1912
Heterochone calyx is a very rare species reported from Oberg (near Ilsede) by Schrammen (1912) as "Chonelasma hindei". It is reported here from Höver for the first time.
The specimen of Heterochone calyx consists of an axial tube (or narrow funnel) with a compact stalk (10 mm thick) and with numerous radially directed, finger-like protrusions (8 to 15 mm diameter, 10 to 25 mm long) in the calyx section. The protrusions show a vague spiralling arrangement. They have 3 to 5 mm wide parietal oscula at their truncated ends, but each protrusion has some conical apendices surrounding the accessory oscula.
The wall thickness of the specimen is slightly more than one mm. Ostia and postica cannot be discerned in the unetched specimen, but are reported in the literature (Reiswig, 2002).