Hancock's organ

Last updated
A microphoto of Hancock's organ (ho) of a sea slug Pseudunela marteli. Pseudunela marteli 4.png
A microphoto of Hancock's organ (ho) of a sea slug Pseudunela marteli .
A microphoto of head region of Pseudunela marteli shows position of Hancock's organ (ho) near eye (ey) and rhinophore (rh). Pseudunela marteli 3.png
A microphoto of head region of Pseudunela marteli shows position of Hancock's organ (ho) near eye (ey) and rhinophore (rh).

Hancock's organ is a lateral concealed sensory organ of gastropods, [1] a chemo-sensory sense organ found in some sea snails. [2] This organ is found in most of the shelled opisthobranchs. [2]

A great majority of the bubble shells and sea slugs of the orders Acteonoidea and Cephalaspidea have Hancock’s organs.

Related Research Articles

Cochlea

The cochlea is the part of the inner ear involved in hearing. It is a spiral-shaped cavity in the bony labyrinth, in humans making 2.75 turns around its axis, the modiolus. A core component of the cochlea is the Organ of Corti, the sensory organ of hearing, which is distributed along the partition separating the fluid chambers in the coiled tapered tube of the cochlea.

Autonomic nervous system Division of the peripheral nervous system supplying smooth muscle and glands

The autonomic nervous system (ANS), formerly the vegetative nervous system, is a division of the peripheral nervous system that supplies smooth muscle and glands, and thus influences the function of internal organs. The autonomic nervous system is a control system that acts largely unconsciously and regulates bodily functions, such as the heart rate, digestion, respiratory rate, pupillary response, urination, and sexual arousal. This system is the primary mechanism in control of the fight-or-flight response.

Gastropoda Class of snails and slugs

The gastropods, commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda.

Bivalvia Class of molluscs

Bivalvia, in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. Bivalves as a group have no head and they lack some usual molluscan organs like the radula and the odontophore. They include the clams, oysters, cockles, mussels, scallops, and numerous other families that live in saltwater, as well as a number of families that live in freshwater. The majority are filter feeders. The gills have evolved into ctenidia, specialised organs for feeding and breathing. Most bivalves bury themselves in sediment where they are relatively safe from predation. Others lie on the sea floor or attach themselves to rocks or other hard surfaces. Some bivalves, such as the scallops and file shells, can swim. The shipworms bore into wood, clay, or stone and live inside these substances.

Chiton Class (Polyplacophora) of marine molluscs

Chitons are marine molluscs of varying size in the class Polyplacophora, formerly known as Amphineura. About 940 extant and 430 fossil species are recognized.

Vomeronasal organ

The vomeronasal organ (VNO), or Jacobson's organ, is the paired auxiliary olfactory (smell) sense organ located in the soft tissue of the nasal septum, in the nasal cavity just above the roof of the mouth. The name is derived from the fact that it lies adjacent to the unpaired vomer bone in the nasal septum. It is present and functional in all snakes and lizards, and in many mammals, including cats, dogs, cattle, pigs, and some primates; in humans and horses it is present, but is vestigial and non-functional.

Nudibranch Order of gastropods

Nudibranchs are a group of soft-bodied, marine gastropod molluscs which shed their shells after their larval stage. They are noted for their often extraordinary colours and striking forms, and they have been given colourful nicknames to match, such as "clown," "marigold," "splendid," "dancer," "dragon," or "sea rabbit." Currently, about 3,000 valid species of nudibranchs are known.

Cephalaspidea Order of gastropods

The clade Cephalaspidea, also known as the headshield slugs and bubble snails, is a major taxon of sea slugs and bubble snails, marine gastropod mollusks within the larger clade Euopisthobranchia. Bubble shells is another common name for these families of marine gastropods, some of which have thin bubble-like shells. This clade contains more than 600 species.

Veliger

A veliger is the planktonic larva of many kinds of sea snails and freshwater snails, as well as most bivalve molluscs (clams) and tusk shells.

Cortex (anatomy)

In anatomy and zoology, the cortex is the outermost layer of an organ. Organs with well-defined cortical layers include kidneys, adrenal glands, ovaries, the thymus, and portions of the brain, including the cerebral cortex, the best-known of all cortices.

In anatomy, a suture is a fairly rigid joint between two or more hard elements of an organism, with or without significant overlap of the elements.

Rhinophore

A rhinophore is one of a pair of chemosensory club-shaped, rod-shaped or ear-like structures which are the most prominent part of the external head anatomy in sea slugs, marine gastropod opisthobranch mollusks such as the nudibranchs (Nudibranchia), Sea Hares, (Aplysiomorpha) and sap-sucking sea slugs (Sacoglossa).

Vetigastropoda Clade of sea snails

Vetigastropoda is a major taxonomic group of sea snails, marine gastropod mollusks that form a very ancient lineage. Taxonomically the Vetigastropoda are sometimes treated as an order, although they are treated as an unranked clade in Bouchet and Rocroi, 2005.

The sensory organs of gastropods include olfactory organs, eyes, statocysts and mechanoreceptors. Gastropods have no sense of hearing.

Sense relates to any of the systems and corresponding organs involved in sensation, i.e. the physical process of responding to stimuli and providing data for perception. During sensation, sense organs collect stimuli for transduction. Sensation and perception are fundamental to nearly every aspect of cognition, behavior and thought.

Most fish possess highly developed sense organs. Nearly all daylight fish have color vision that is at least as good as a human's. Many fish also have chemoreceptors that are responsible for extraordinary senses of taste and smell. Although they have ears, many fish may not hear very well. Most fish have sensitive receptors that form the lateral line system, which detects gentle currents and vibrations, and senses the motion of nearby fish and prey. Sharks can sense frequencies in the range of 25 to 50 Hz through their lateral line.

<i>Onchidoris proxima</i> Species of gastropod

Onchidoris proxima is a species of sea slug, a dorid nudibranch, a shell-less marine gastropod mollusc in the family Onchidorididae. This species is found in the northeastern and northwestern parts of the Atlantic Ocean. It is also reported from the northeastern Pacific Ocean. Previously in the genus Adalaria this species was moved to Onchidoris as a result of a molecular phylogeny study.

<i>Jorunna parva</i> Species of gastropod

Jorunna parva, popularly known as "sea bunny", is a species of dorid nudibranch, a shell-less marine gastropod mollusc in the family Discodorididae. It is found along the coasts of Korea, Japan, Palau, Philippines, Indonesia, Papua New Guinea, Australia, South Africa, Seychelles, and Tanzania. The species was first described by Kikutaro Baba. The resemblance of Jorunna parva's rhinophores to a rabbit's ears and its other features facilitated a surge in popularity on Twitter throughout Japan in 2015. The rhinophores are classified as sensory organs for the act of chemoreception. The rhinophores indeed enhance detection efficiency and allow Jorunna parva to sense its surrounding environment. The receptors allow these species to locate their mates and forage for food resources as well. Sea bunnies, like many other nudibranchs, eat sponges, which contain toxins. Those toxins are used for cancer treatments. A chemical compound called "jorumycin" has been found in a related species, Jorunna funebris. This compound is a tetrahydroisoquinoline, meaning it contains the same basic chemical backbone as an antitumor drug called PM00104, or Zalypsis, which is meant to be injected intravenously. Sea bunnies are considered to be one of 16 species in the family Discodorididae. The fur is called caryophyllidia, which is composed of fleshy protuberances called papillae, as well as spicules, which are used for sensory functions.

This outline is provided as an overview of, and organized list of articles relevant to, the subject of gastropods :

<i>Tonicella marmorea</i> Species of mollusc

Tonicella marmorea is a species of chiton, a polyplacophoran mollusc found in the Arctic Ocean and the North Atlantic Ocean. It was first described by the Danish missionary and naturalist Otto Fabricius.

References

  1. Hancock, A., (1852). Observations on the Olfactory Apparatus in the Bullidae. The Annals and Magazine of Natural History Vol.IX – Series 2 188-190.
  2. 1 2 Schrödl M. & Neusser T. P. (2010). "Towards a phylogeny and evolution of Acochlidia (Mollusca: Gastropoda: Opisthobranchia)". Zoological Journal of the Linnean Society 158: 124-154. doi : 10.1111/j.1096-3642.2009.00544.x.