Hermissenda crassicornis is a nudibranch mollusc. Farley and Kim Blackwell (2008)
Nervous system organization
The nervous system of Hermissenda consists of a paired Cerebropleural ganglion (CPG)and a pair of Pedal Ganglia (PG). There is also a Buccal ganglion, not shown in figure.
- P1 (nerve 1) extends from the posterior pedal ganglion. It innervates the anterior body wall and foot. Backfills show hundreds of cell bodies distributed over entire pedal ganglion, several cell in ipsilateral pleural ganglion, and a small number of cells in ipsilateral cerebral ganglion and contralateral pedal ganglion (Richards and Farley, 1987).
- P2 (nerve 2)extends from the lateral pedal ganglion and innervates the anterior portion of the body. Backfills showed clusters of cell bodies particularly on ventral surface of the ipsilateral pedal ganglion (MN4 cells) and ipsilateral pleural ganglion. Also MN3 and MN4 were filled. Two unidentified neurons and a cluster of 4-5 smaller neurons were filled in the contralateral pleural ganglion (Richards and Farley, 1987).
- P3 (nerve 3) extends from the anterior pedal ganglion.
- nerve4 extends from the posterior pleural ganglion.
List of identified neurons in Hermissenda
- Type I interneuron
- Ib interneuron
- Type II interneuron
- Optic Ganglion
- Inhibitory interneurons (IIIi)
- Type A
- Type B
- Pedal Ganglion
See Hermissenda_References for complete list
- Crow T, Tian LM (2003) Interneuronal projections to identified cilia-activating pedal neurons in Hermissenda. J Neurophysiol 89:2420. Pubmed ID: 12740402
- Crow TJ, Tian LM (2009) Polysensory Interneuronal Projections to Foot Contractile Pedal Neurons in Hermissenda. J Neurophysiol. 101(2):824-33 Pubmed Pubmed ID: 19073803
- J.Farley and K. Blackwell (2008), Scholarpedia, 3(7):4090 
- T. P. Jerussi and D. L. Alkon. Ocular and extraocular responses of identifiable neurons in pedal ganglia of Hermissenda crassicornis. J.Neurophysiol. 46 (3):659-671, 1981 Pubmed ID: 7299440.
- Richards WG, Farley J. Motor correlates of phototaxis and associative learning in Hermissenda crassicornis. Brain Res Bull. 1987 Aug;19(2):175-89. PubMed ID: 3664278