Fig. 55 in Early-middle Cambrian stratigraphy and faunas from northern Siberia

Fig. 55. Hyolithid helens from the lower Cambrian Erkeket Formation, Khorbusuonka River (A, B, E, F) and Tyuser (D) and Sekten (C) formations, lower reaches of the Lena River, Siberia, Russia; samples 19/10.75 (A, B, E), 20/1B (F), 21/21 (D), and 22/50 (C). A–F. Phosphatized hyolithid appendages (helens), SMNH X11230–11235, respectively. A2, enlargement of A1 showing proximal end; B1, upper surface; B2, oblique view on the upper and frontal (left side in B1) surfaces; B3, view on the rear margin of the helen (right side in B1); B4, close-up of proximal portion; E1, oblique lateral view; E2, F1, plain view; F2, F3, view on the margin (left side in F1). Scale bar: 500 µm (C, D), 250 µm (A1, B1–B3, E, F), 80 µm (A2, B4).