A second bursa copulatrix (a sperm pouch that receives sperm during copulation).
A lobe attached to the penis.
Prolonged dormancy – usually to avoid drying or cold.
A gland associated with the oviduct.
Two or more species (or populations) not sharing the same locality.
Used for taxa or populations that occur in separate and non-overlapping geographic areas.
Pertaining to the front end of the animal.
At the apex.
Changed from the primitive state.
Relating to the base.
The community on the floor of a lake, river or stream (or on the ocean floor).
Concave above and below.
A structure divided into two projections.
Branching into two projections.
A cut-off lake formed by a meandering river (also called oxbow lakes).
With two lobes.
Divided into two branches.
Water with a salinity in between fresh water and seawater.
Relating to the gills.
An chamber within the animal or part of the shell in which eggs are brooded.
A sperm sac in which sperm is deposited - usually directly by the copulating partner. See also spermathecal gland.
The duct of the bursa copulatrix.
One or more attachment threads produced by the byssal gland in the foot of many autobranch bivalves
Pouch-like projection from a chamber, such as the stomach.
Primarily consisting of the mineral calcium carbonate (CaCO3).
Forming a channel.
A gland associated with the oviduct.
Short teeth that radiate from the umbo of a bivalve - part of a heterodont hinge.
A prominent spiral ridge.
With one or more carinae.
The middle tooth of each row of teeth of the radula. Sometimes called the rhacidian tooth.
An inverted V-shape.
A polymer similar in structure to glucose. Combined with protein it forms the exoskeleton in many invertebrates.
Thin processes that extend from epithelial cells - usually motile but some are stationary.
Feeding where food is captured on the gills using the cilia on the gill filaments – often called filter feeding or suspension feeding.
A rank within the hierarchy of taxonomic classification. It is the main category between phylum and order.
A process of establishing, defining and ranking taxa within hierarchical series of groups.
Embryos or adults that share an identical common ancestry (i.e., not produced by sexual reproduction).
Lines with a common centre.
In the shape of a cone.
Tissue that connects, binds or supports organs and other tissues (usually rather amorphous).
Of the same species.
Twisted or coiled.
A section or part of the body used to facilitate internal fertilisation by transferring sperm.
Distinct but fine ribbing.
Hidden or camouflaged.
A hyaline rod of mucoprotein found in the style sac of some gastropods and many bivalves.
The filaments that make up the ctenidium.
The original molluscan gill (secondary gills are also found in molluscs) which is comprised of filaments. It is paired in bivalves and in its primitive state in gastropods, although all freshwater gastropods have a single ctenidium or none.
Half of a bivalve ctenidial filament - these are typically W- shaped and divided into a V-shaped inner and outer demibranch.
A small projection.
Toothed, or with short ridges.
Somewhat flattened.
A partition.
With two ducts.
Two forms (usally based on size) of the same species. Mostly related to sex (sexual dimorphism) but can be used for other morphotypes such as colour or shape. Compare with polymorphism.
Having separate sexes (male and female).
When an embryo develops through to hatching as a juvenile without going through a free-living larval stage.
Not joining or meeting. Often applied to distributions.
Away from the middle of the body or point of attachment.
With a diverticulum.
Blind process or pocket.
The surface of an animal furthest away from the ground or other support, in other words upper surface.
On the upper sides of the animal.
On the lower sides of the animal.
Off-centre.
Study of the relationship among organisms and that to their physical surroundings.
Process in which the relative movement of proteins is examined in an electric field.
Oval or egg-shaped.
Of a long shape.
Found only in a particular geographical area.
Transitory, fleeting.
Fauna on the surface.
Two shell valves the same size and shape (cf. inequivalve) (bivalves).
A condition of bivalve gills where the gills are jointed by fleshy connections.
The union of a male and female gamete to form a zygote occurring outside the body of an animal typically in the water column.
No longer in existence, no longer living.
Waste material excreted from the gut of an animal.
A rank in a taxonomic classification between an order and genus.
The entire animal life of a given region, habitat, or geological stratum.
The union of a male and a female gamete to form a zygote, sometimes referred generally to the act of insemination, impregnation or pollination.
A condition of bivalve gills where the gills are jointed by ciliary connections.
Feeding where food is captured on the gills using the cilia on the gill filaments – commonly called ciliary feeding or suspension feeding.
Split or cracked.
A whip-like structure on a cell. For single cells such as spermatozoa, it is the motile structure.
Flame-like markings.
An organism, fragment, impression or trace of an organism preserved in a rock.
Water with a salinity of less than 0.5 parts per thousand, or alternatively, less than 2 parts per thousand (seawater is commonly around 35 parts per thousand).
Tapering at both ends; spindle-shaped.
A caecum attached to the stomach.
A chitinous shield-like structure in the stomach.
A specialised respiratory surface. In molluscs, this is typically the ctenidium, however it may also be a secondary structure.
With glands.
Rounded, globe-like.
The parasitic, bivalved larva of unionoidean bivalves (including Hyriidae).
A duct transporting eggs or sperm.
Covered in granule-like pustules.
Where both male and female reproductive organs are present in the same individual. Consecutive hermaphroditism is where the male and female organs do not occur in the individual at the same time, but successively. Simultaneous hermaphroditism occurs when the male and female reproductive organs occur in the individual at the same time.
A condition where the protoconch is coiled in a different plane or different direction from the adult shell.
A gland on the roof of the mantle cavity in many gastropods and some bivalves.
A larval stage is present in development.
The innermost marginal teeth of the radula.
The union of a male and female to transfer sperm enabling the gametes to form a zygote inside the body of an animal.
The part of the shore covered by high tide and uncovered at low tide.
Folded inwards like the finger of a glove.
Animal without a backbone or spinal column.
Showing a variety of colours when viewed from different angles.
The chitinous structure in the oral tube or outer part of the buccal cavity of gastropods – commonly primitively paired, but single (dorsal) in some.
An organism not yet fully developed, with features of both the larval stage and the adult stage.
Topography formed when rocks (typically limestone) are dissolved. Commonly rugged in shape.
Two pairs of flap-like structures on either side of the mouth in bivalves.
Raised thin ridges.
With laminae.
A developmental form of an organism, without adult characteristics and unable to reproduce.
From or on the side.
A tooth that lies along the hinge line and is part of a heterodont hinge (see cardinal tooth). Or one or more radular teeth that lie next to the central teeth.
Still waters (as in lakes).
Lens-shaped.
A cap-shaped shell – this type of shell morphology has been achieved convergently in many different gastropods and a few bivalves.
Spiral ridges or cords.
Forming lobes.
Flowing waters (as in streams or rivers).
Crescent-shaped.
Large aquatic plants (cf. algae).
Brood chamber in a bivalve gill where the bivalve parent is providing nutrients to the developing embryos.
Middle, or towards the middle.
The middle cusp or denticle on a radular tooth – equivalent to the main, median or central cusp.
Relating to the metapodium.
Very fine costae (ridges).
Fine sculpture, often not visible in detail using an ordinary light microscope.
The form and structure of an organism, with special emphasis on the external features.
The slimy substance secreted by goblet cells onto the surface of a mucus membrane to protect, lubricate and trap bacteria, dust, etc.
Of several to many spirals or whorls (cf. paucispiral).
Mother of pearl – a special kind of iridescent shell layer.
Kidney.
Shaped like the marine genus Nerita.
The ring of ganglia and their connectives surrounding the buccal area or the oesophagus.
Groove on neck that runs on to the side of the foot from the mantle cavity.
Pegs on the inner side of the operculum that provide additional surface for muscle attachment.
Leaning backwards relative to the coiling axis (cf. orthocline and prosocline).
Bivalve with beaks pointing posteriorly (cf. orthogyrate and prosogyrate).
Pertaining to the mouth.
A rank in a classification between class and family.
Pertaining to or derived from living organisms, or to compounds containing carbon as an essential component.
Perpendicular relative to the coiling axis (cf. prosocline and opisthocline).
Bivalve with beaks not pointing anteriorly or posteriorly (cf. opisthogyrate and prosogyrate).
A normal coil.
A chemosensory organ in the mantle cavity.
An oval shape.
A structure that transports eggs from the gonad to the exterior. In gastropods with internal fertilisation, the eggs are fertilised in the duct and surrounded by nutrients and a covering secreted from associated albumen and capsule glands before being released.
Eggs are laid which develop outside the body of the parent.
Of an oval shape.
A gonad that produces both sperm and eggs.
Similar to viviparous species where the eggs are internally fertilized and the young are born as larvae or juveniles, but differ in not obtaining nourishment from the parent other than by egg yolk.
Equivalent to mantle cavity.
Tentacles attached to the edge of the mantle.
Short finger-like structures (plural 'papillae').
With papillae.
The development of an organism from an unfertilised egg.
A female that can produce eggs that develop as embryos without the involvement of a male.
Of few spirals or whorls (cf. multispiral).
Relating to the foot.
A slit in the sole of the foot into which pedal glands open.
A non-glandular lobe on the penis.
The male copulatory organ.
Condition in which an umbilicus is present in a gastropod shell (cf. imperforate).
A thin-walled chamber containing the heart.
Pertaining to the periostracum.
An organic layer on the outside of the shell. The periostracum may be thin and nearly invisible, thick, or in some species covered with hairs or other ornamentation.
Pertaining to the periphery.
A rank in the hierarchy of classification that is immediately below kingdom.
Coiled in one plane (flat, with no spire).
Three or more forms of the same species. The most common form of polymorphism is different colour varieties.
The part of an animal that is towards the rear (i.e. that which follows when the animal is moving).
The invertible sheath into which the penis retracts in many heterobranch gastropods.
An organism that feeds by preying on other organisms, killing them for food.
Leaning forwards relative to the coiling axis (cf. orthocline and opisthocline).
Bivalve with beaks pointing anteriorly (cf. orthogyrate and opisthogyrate).
A gland in the male genital tract.
A duct of the prostate gland.
Hermaphrodite that first develops as male and then becomes female.
The larval or embryonic shell in a gastropod (cf. teleoconch).
A rotating mucoid rod that lies in the style sac.
The hinge teeth of some unionoidean bivalves that are short and close to the umbones, and resemble the cardinal teeth of heterodont bivalves.
A modified mantle cavity which in pulmonates functions as a lung.
Shaped like Pupa, a small, bullet-shaped land snail.
Small raised, rounded spots.
Covered with pustules.
Pear-shaped.
Approximately square or rectangular.
An anatomical structure that is used by molluscs for feeding, sometimes compared to a tongue. It is a minutely toothed, chitinous ribbon, typically used for scraping or cutting food. Absent in bivalves and a few gastropods.
A gland-like structure in the kidney.
Of net-like appearance.
A muscle that, when it contracts, withdraws a structure.
An alternative name for the central radular teeth.
Main axis of shaft.
Rhombus-shaped (i.e., a flat shape with four equal straight sides, for example diamond-shaped).
Fat, rounded.
Reduced, hardly present (similar to vestigial).
Ridges.
Of rough texture.
Mucus- or, less commonly, enzyme-producing glands that open into the buccal cavity.
The structure forming the tip of the everted preputium, through which the penis passes in copulation.
An undulating edge or fluted edge.
The type of hinge seen in unionoidean bivalves, and in the marine Trigoniidae.
Particulate matter that has been transported by wind, water or ice and subsequently deposited, or that has been precipitated from water.
The division of a body or appendage into a linear sequence of similar units.
A sperm sac in which sperm is stored after copulation.
A swelling or pocket in the vas deferens of the male in which sperm is stored.
Stiff, minute hair-like structures.
When males and females differ in shape and/or size.
The hard outer covering of a wide variety of invertebrates and notably molluscs. Mollusc shells are mineralised with calcium carbonate (CaCO3).
A (typically large) hole in the ground (commonly in limestone).
Winding, with few to many bends.
Spatula or spoon-like.
A group of organisms (or other entities) distinct from other groups. Also a taxon of the rank of species in biological classification that is the category below genus. Used in this latter sense, it is the basic unit of biological classification.
A sac containing sperm in the female system.
The duct of the spermathecal gland.
A sperm sac in the female system which receives sperm during copulation. Equivalent to the bursa copulatrix but this term is usually used in euthyneuran heterobranchs.
A packet containing sperm that is passed from male to female in some molluscs.
The sac-like extension of the stomach in which the crystalline style or protostyle is contained.
Weakly angled.
Near central.
Almost gone, or almost absent.
Somewhat resembling a pupiform shape.
The sediment, surface or medium to which an organism is attached or upon which it grows, substratum.
Near terminal.
Somewhat trochiform in shape.
Near the umbone.
Above the anus.
Above the foot.
See filter feeder.
Two or more species living in the same location (cf. allopatric).
A radular configuration of seven teeth in each row.
The theory and practice of describing, naming and classifying organisms (also referred to as systematics).
The ‘adult’ whorls of a gastropod shell (cf. protoconch).
With three cusps.
Shaped like the marine genus Trochus.
Shortened or cut off.
With an umbilicus.
A single arm-like structure.
Without articulation.
The terminal part of the female reproductive system in euthyneruans.
A pouch associated with the vagina.
A tube carrying the sperm from the testis to the penis in the male.
Describing the surface of an animal that is nearest or next to the ground or other support.
A swelling or pocket.
An expanded pouch.
Similar to rudimentary.
See viviparous.
Producing live offspring from within the body of the parent.
Microscopic green ‘algal’ cells that form symbiotic relationships with some molluscs (e.g. giant clams) and corals.
