Neurons in Lymnaea

Maps of neurons on the dorsal (a) and ventral (b) surfaces of the Lymnaea CNS, showing the location of serotonin (shaded) and non-serotonin- (unshaded) containing cells. The cerebral ganglia are shown with the cerebral commissure cut and the left and right ganglion folded out to give a flattened, two-dimensional view of the CNS. Identified cells are labelled in the right pedal, identified clusters labelled in the left pedal ganglion. Both have symmetrical equivalents in the contralateral ganglion.

picture ofdorsal surface picture of ventral surface


  1. Dorsal view of the CNS except for the cerebral ganglia which are shown mainly in medial view.
  2. Ventral view of the CNS with the cerebral ganglia shown in mainly lateral view.
  3. Detail of the buccal ganglia; Compare a photomicrograph of the living brain
  4. Detail of parietal ganglia

Ganglia: buccal (b,.g); cerebral (cr.g.); pedal (pd.g.); pleural (pl.g.); parietal (pa.g.); and visceral (v.g.). L, R and 1, r indicates left and right; A, P indicates anterior and posterior.

Lobes of the cerebral ganglia: anterior (al); ventral (vl); and dorsal (dl).

Major nerves, connectives and commissures:

  1. postbuccal nerve
  2. buccal commissure
  3. dorsobuccal nerve
  4. laterobuccal nerve
  5. ventrobuccal nerve
  6. cerebro-buccal connective [cut]
  7. superior lip nerve
  8. median lip nerve
  9. cerebral commissure [cut in midline]
  10. superior pedal nerve
  11. median pedal nerve
  12. inferior pedal nerve
  13. left parietal nerve
  14. cutaneous pallial nerve
  15. anal nerve
  16. intestinal nerve
  17. genital nerve
  18. internal right parietal nerve
  19. external right parietal nerve

This summarises the data from immunostaining, 5,6- or 5,7-DHT pigment labelling, and glyoxylic acid staining.

Modified from maps in Kemenes et al, (1989) J. Neurocytol 18:193ff, and Vehovszky & Elliott, (2001, in press)