![Aulacostephanus (aulacostephanoides) mutabilis](http://www.geoed.co.uk/cdn/shop/products/pictrilonew_95fed88d-98fd-42ea-9c99-290f5c7667b0_{width}x.png?v=1581676489)
A very fine wholly septate internal mould showing excellent preservation of the secondary ribs and sutures. A more inflated form than KIM 4.0A. From England, UK.
Size: 91mm diameter
Size: 91mm diameter