Fig. 5 in Morphology of larval and postlarval stages of Priapulopsis bicaudatus (Danielssen, 1869) (Priapulida) from the north atlantic ocean

Fig. 5. Introvert of the larva. A. Fully everted introvert showing the division into neck (ne), scalid region (sc) and mouth cone (mc). The primary scalids (ps) are directed anteriorly, the ring 2-scalids are marked by an arrow. ru = ruff. B. Arrangement of the 8 primary scalids (ps1-ps8), the ring 2-scalids (asterisks) and the further scalids (sc). The edge of two pharyngeal teeth (pt) is visible. C. Magnification of the mouth cone and the primary scalids (ps). The dashed line indicates a virtual line, along which scalids are arranged on both sides. The white line marks a row of scalids between primary scalids, the asterisk marks the first, larger scalid in these rows. D. Scalids are arranged in longitudinal rows. E. The broad, leaf-like scalids are have a margin (ma), a pair of tube-like structures (arrows) and a fringe (fr). F. Magnification of the "inner" region of the apical end of a primary scalid. G. Side view on a primary scalid. H. Back side of a primary scalid with several spines. All images SEM. A from V13489, B, D-H from three different specimens of V13478, C V13495.