Fig. 3
From: Embryonic and early juvenile development in the Silurian basal nautilid Peismoceras Hyatt, 1894
Peismoceras asperum (Barrande, 1865), lectotype (SD, here) NM-L 7918 (Barrande 1865, pl. 16, figs 8–11), Ludlow, Gorstian, lower scanicus-chimaera Biozone, Kopanina Formation, Bohemia, Praha-Malá Chuchle, Vyskočilka locality (for location see Manda and Kříž 2007); lateral view (b) and details of body chamber base showing annular elevation with laterally situated attachment area of a pair of retractor muscles and imprints of radial septal arteries known in nautilids (see Deecke 1913; Klug et al. 2008): dorsal (a), right lateral (c), ventral (d) and left lateral (e) views. Scale bar 1 cm. ae annular elevation, ap aperture, dlw divergent last whorl, lr lateral retractor muscle scars, lrb last rib, mmb mantle myoadhesive band, rai radial arteries imprints on septum, s suture line, smb septal myoadhesive band