Fig. 6. Damesites sugata Forbes, 1846. A in Precursory siphuncular membranes in the body chamber of Phyllopachyceras and comparisons with other ammonoids

Fig. 6. Damesites sugata Forbes, 1846. A. UMUT MM 28661 from the middle Campanian in the Nio River, Nakagawa area, north Hokkaido. B. UMUT MM 28662 from the middle Campanian in the Nio River, Nakagawa area, north Hokkaido (all in median longitudinal section). A1. Unusually long septal neck, extending into the body chamber, showing locations of photo A2; its length is equivalent to the last cameral distance. A2. Anterior margin of the long septal neck, consisting of a nacreous layer. B1. Unusually long septal neck, extending into the body chamber, showing locations of photo B2; its length is equivalent to the last cameral distance. B2. Anterior margin of the long septal neck, consisting of a nacreous layer. Abbreviations: bc, body chamber; n, nacreous layer of septal neck; s, septum; sn, septal neck.