Fig. 3 in New serpulid polychaetes from the Permian of western Sicily

Fig. 3. Serpulid polychaete "Serpula" calannai sp. nov. (holotype MSNC 4549-33) from the Wordian to upper Permian, "Pietra di Salomone" Limestone, Sicily, Italy. A. Tube fragment before assembling. Growth direction, inferred from the slightly flaring peristomes, marked by an arrow. B. Detail of a peristome and growth lines. C. Longitudinal fracture of tube displaying wall section and inner surface covered by secondary crystals. D. Oblique view of tube showing prominence of ornamentations. E. Detail of C showing layered structure of tube wall, only locally preserved. F. Circular cross section of tube, with relatively thick wall locally showing its likely original layering. All SEM images.