Overview of the central nervous system ( E. fraudatrix ) on paraffin sections stained with Heindenhein's azan. A. Transverse section showing the radial nerve cord (rnc) and other radial organs, including the longitudinal muscle band (lm), radial water-vascular canal (rc), and the hemal lacuna (h). B. Higher magnification of the radial nerve cord shown in (A). Basal processes of glial supporting cells can be clearly seen in the neuroepithelia (arrowheads). C. Sagittal section through the pharyngeal bulb, showing the nerve ring. en, ectoneural neuroepithelium. The oral end of the animal is to the right. cec, circular epineural canal of the nerve ring; ec, epineural canal; en, ectoneural neuroepithelium; hc, hyponeural canal; hn, hyponeural neuroepithelium; re, non-neural roof epithelium; t, hydrocoelic lining of the tentacle. Scale bars = 100 μm in (A) and (B), 50 μm in (C).