Figure 10

Crenubiotus crenulatus s.s. (Richters, 1904) from Spitsbergen: buccal apparatus seen in PCM. (a) Dorsal projection of the entire buccal apparatus. (b) Dorsal view of the oral cavity armature. (c) Ventral view of the oral cavity armature. (d) Lateral view of the anterior portion of the buccal apparatus. (e) Ventral view of placoids. Empty flat arrowheads indicate dorsal spikes, filled indented arrowheads indicate the ventral thickening/additional ridge on the ventral lamina, empty indented arrowheads indicate the third band of teeth in the oral cavity armature, the arrow indicates the putative dorsal residual apophysis, filled flat arrowheads indicate constrictions in the macroplacoids. Scale bars in μm.