Fig. 6 in The tarphyceratid cephalopod Trocholites in the Middle-Upper Ordovician of the Prague Basin -the Baltican element in peri-Gondwana

Fig. 6. Tarphyceratid cephalopod Trocholites chaloupkai sp. nov. from Praha-Štěrboholy, central Bohemia, Czech Republic, upper part of the Zahořany Formation (lower Katian, Upper Ordovician). A. Holotype NM L 63626, detail of apicalmost part of the phragmocone (A1) and drawing (A2) indicating line of contact of whorls, position of siphuncle, position of (partly fragmented) septa and shape of initial chamber and umbilical window.