Table 2.

Innervation of CSOs by cerebral nerves; categories of CSOs

Nerve	Aplysia punctata	Archidoris pseudoargus	Pleurobranchea meckeli	Acteon tornatilis[10]	Haminoea japonica[11]	CSO categories
N1	lip	lip	lip	lip	lip / anterior cephalic shield	no category
N2 inner branch	basal part of the labial tentacle	inner part of the oral tentacle/oral lobe	oral veil	anterior groove among the anterior cephalic shield	lip organ	ASOa
N2 outer branch	tip of the labial tentacle	outer part of the oral tentacle/oral lobe	labial tentacle	posterior groove among the anterior cephalic shield	anterior Hancocks organ	ASOb
N3	rhinophore	rhinophore	rhinophore	possibly reduced in Acteon	posterior Hancocks organ	PSO
Nclc	anterior/lateral body wall	anterior/lateral body wall	anterior/lateral body wall	posterior cephalic shield	posterior cephalic shield	no category