Plagiostomoceras aff. angustum (Holzapfel, 1895) from the early Famennian, Jablonna, Holy Cross Mts., Poland; reconstruction of the body chamber (a); longitudinal section through a siphuncle (b), bed J. 11; variability of the septal suture (c; equally variable is the siphuncle position).

Plagiostomoceras aff. angustum (Holzapfel, 1895) from the early Famennian, bed J . 11, Jabłonna, Holy Cross Mts., Poland. 1.  Body chamber in ventral? (a) and lateral (b) views. 2. Subadult specimen in ventral (a) and lateral (b) views.