Fig. 9
From: The complex simplicity of the brittle star nervous system
Organization of the hyponeural part of the radial nerve cord (RNC) in A. kochii. Transmission electron microscopy. a and b Hyponeural system in the interganglionic region of the RNC. a Low-magnification view of the hyponeural cord. b Part of the oral wall (floor) of the interganglionic hyponeural cord formed by flattened glial cells with no neuronal elements. c–g Hyponeural system in the ganglionic swelling of the RNC. C Secretory radial glia. d Neurosecretory-like cell in the aboral wall (roof) of the hyponeural cord. e and f Abundant neurons in the oral wall (floor) of the hyponeural cord. f Giant neuron. g High-magnification view of a muscle bundle integrated in the lateral region of the hyponeural neuroepithelium. Abbreviations: bp – basal process of radial glial cell; en – ectoneural neuroepithelium; gc – flattened glial cell; gn – “giant” neuron; hc – lumen of the hyponeural canal; hl – hemal lacuna; hn – hyponeural neuroepithelium; m – bundle of muscle cells; np – neuronal processes; nsc – neurosecretory-like cell; rg – radial glia