Fig. 3 in Morphology and ontogeny of some Middle Ordovician gonambonitid brachiopods from Baltoscandia

Fig. 3. Gonambonitid brachiopod Anchigonites conulus Öpik, 1939 from the Kunda regional stage, Darriwilian, Middle Ordovician of the Leningrad Region, Russia, ontogenetic series of ventral valves. A. PIN 4921/798, 3.5 mm wide valve in exterior (A1) and interior (A2) views. B. PIN 4921/891, 5 mm wide valve with sealed pedicle tube in interior view (B1), spondylium (B2), apical disc infilling the delthyrium apex (B3). C. PIN 4921/911, 4.2 mm wide valve in lateral (C1), ventral (C2), and posterior (C3) views. D. PIN 4921/908, 7 mm wide valve in general (D1) and lateral (D2) views. E. PIN 4921/807, 5.5 mm wide valve in general view (E1), spondylium with rudiment lateral septa (E2). F. PIN 4921/895, 8.3 mm wide valve in general (F1) and lateral (F2) views. G. PIN 4921/913, broken apical disc with imprint of the substrate, general view (G1), enlarged surface of the attachment region (G2).