Fig. 9 in Revision of Middle Ordovician orthoceratacean nautiloids from Baltoscandia

Fig. 9. Longitudinal section of the siphuncle of Nilssonoceras latisiphonatum sp. nov., NRM−Mo 158037, holotype (diameter of the siphuncle 10 mm). The siphuncle shows different areas of sparite (dotted: fin grained calcite, medium hatched: medium grained sparite, coarsely hatched: coarse grained sparite) which are interpreted as residues of the spherulitic prismatic layer of the connecting ring (dotted), the endosiphonal annuli (medium hatched) and the endosiphuncular lining (coarsely hatched).