Hancock's organ is a lateral concealed sensory organ of gastropods,Hancock, A., (1852). Observations on the Olfactory Apparatus in the Bullidae. The Annals and Magazine of Natural History Vol.IX – Series 2 188-190. a chemo-sensory sense organ found in some

sea snail Sea snails are slow-moving marine (ocean), marine gastropod Mollusca, molluscs, usually with visible external shells, such as whelk or abalone. They share the Taxonomic classification, taxonomic class Gastropoda with slugs, which are distinguishe ...

s. This organ is found in most of the shelled

opisthobranch Opisthobranchs () is a now informal name for a large and diverse group of specialized complex gastropods which used to be united in the subclass Opisthobranchia. That taxon is no longer considered to represent a monophyletic grouping. Euopistho ...

s.Schrödl M. & Neusser T. P. (2010). "Towards a phylogeny and evolution of Acochlidia (Mollusca: Gastropoda: Opisthobranchia)". ''

Zoological Journal of the Linnean Society The ''Zoological Journal of the Linnean Society'' is a monthly peer-reviewed scientific journal covering zoology published by Oxford University Press on behalf of the Linnean Society. The editor-in-chief is Maarten Christenhusz (Linnean Society) ...

'' 158: 124-154. . A great majority of the bubble shells and

sea slug Sea slug is a common name for some Marine biology, marine invertebrates with varying levels of resemblance to terrestrial Slug, slugs. Most creatures known as sea slugs are gastropods, i.e. they are Sea snail, sea snails (marine gastropod moll ...

s of the orders

Acteonoidea Acteonoidea is a superfamily of sea snails, or bubble snails, marine gastropod mollusks. Taxonomy In the taxonomy of Bouchet & Rocroi (2005), the superfamily Acteonoidea has been included into the informal group "Lower Heterobranchia" (He ...

and

Cephalaspidea The order Cephalaspidea, also known as the headshield slugs and bubble snails, is a major taxon of sea slugs and bubble snails, marine (ocean), marine gastropod mollusks within the larger clade Euopisthobranchia. Bubble shells is another commo ...

have Hancock’s organs.

References

Gastropod anatomy {{gastropod-stub