Figure 1..

The somatic (red) and visceral (blue) nervous systems in mollusks and vertebrates. (a) In mollusks, the pedal cord interconnects the preoral cerebral ganglia (ceg) with the postoral pedal ganglia (peg). The visceral cord interconnects visceral ganglia (vig), pleural (plg) and buccal ganglia (bug), forming a second ring around the gut. (b) The same ganglia shown in an adult snail from a lateral view. (c) In vertebrates, roman numerals (I to XII) label the cranial nerves. syg, sympathetic ganglia.

Bertucci and Arendt BMC Biology 2013 11:54   doi:10.1186/1741-7007-11-54
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