File:Schematic diagram of the anterior central nervous system (CNS) and stomatogastric system (STNS) of an astacid decapod.jpg

English: Fig. 2. A. Schematic diagram of the anterior central nervous system (CNS) and stomatogastric system (STNS) of an astacid decapod, in ventral view. The four principal ganglia of the STNS (coloured) are a semi-autonomous unit of the nervous system that is derived from the stomodaeum (note the close proximity of its ganglia in all cases to the gut), and only secondarily becomes attached to the CNS. The commissural ganglion is thus not part of the tritocerebrum, even if it can become fused with it (Biffis, 2017). Note that the dorsal ventricular nerve and its associated stomatogastric ganglion lie along the dorsal surface of the gut. The labral nerve leads to the labrum from the inferior oesophageal nerve. Modified from Vilpoux et al. (2006), Bitsch and Bitsch (2010) and Biffis (2017). B. The same, in slightly rotated lateral view showing the relationship of the STNS to the gut. Labrum shown schematically in grey. Modified from Skiebe (2001).