Fig. 3
Digital 3D-Reconstruction of the anatomy of Bathochordaeus stygius. A Complete trunk in oblique view from the left. Epidermis is semi-transparent to show inner organs. Note the dorsally oriented mouth opening. B Dorsal view with dotted rectangle highlighting mouth pharynx and central nervous system. C Enlarged dorsal view of the rostral region highlighted in (B). Note the symmetrical arrangement of sensory organs on the margin of the mouth and the inner rostral pharynx. D Schematic illustration of the oral region and nervous system in B. stygius with distribution of the oral sensory organs and innervating nerves. cf—ciliary funnel, cr—ciliary ring of gill slit, n2l/r—second brain nerve of left/right side, n3l/r—third brain nerve of left/right side, nc—nerve chord, osoal/r—anterior oral sensory organ of the left/right side, osoll/r—lateral oral sensory organ of the left/right side, osoil/r—inner oral sensory organ of the left/r side, ph—pharynx