Fig. 49 in Early-middle Cambrian stratigraphy and faunas from northern Siberia

Fig. 49. Hyolith opercula "Orthothecid operculum type C", from the lower Cambrian Erkeket Formation, Khorbusuonka River (A–D) and Tyuser Formation, lower reaches of the Lena River (E–G), Siberia, Russia; samples 11/2B (A–D) and 21/21 (E–G). A–G. Phosphatised opercula, SMNH X11196–11202, respectively. E1, inner surface and transverse broken view; E2, enlargement showing fibrous composition of the wall; F1, ventral view; A1, C1, F2, outer surface; A2, C3, dorsal view; A3, lateral view; C2, oblique lateral view; D1, oblique inner surface view; D2, enlargement showing pitted inner surface. Scale bar: 500 µm (A, C, D1, E1, F) and 250 µm (B, D2, E2, G).