Adventitious avicularium: One occupying a position on the frontal shield of an autozooid.
Alveoli: Extrazooidal spaces between the autozooids of rectangulate cyclostomes.
Ancestrula: First-formed zooid of a colony, derived by metamorphosis of a free-swimming larva.
Anter: Part of the orifice distal to the condyles in ascophoran cheilostomes.
Apertural bar: Fused pair of costae immediately proximal to the orifice in cribrimorph cheilostomes.
Areolar pore: Marginal pore in the frontal shield of some cheilostomes.
Ascopore: Marginal frontal pore/s which serves as inlet of the ascus in some ascophoran cheilostomes.
Ascus: Sac-like hydrostatic organ in ascophoran cheilostomes, that fills with seawater when the tentacles are protruded.
Autozooid: Feeding zooid.
Avicularium (pl. Avicularia): Specialised zooid in cheilostomes with reduced polypide but strong muscles which operate a hypertrophied, mandible-like operculum.
Basal: Underside of an encrusting or freely-living colony.
Basal lamina: Basal wall of the cyclostome colony visible at the growing edge.
Bifoliate: Colony formed of two layers of zooids back-to-back.
Cancelli: Kenozooids or extrazooidal spaces between the autozooids of cancellate cyclostomes.
Capitulum: The apical group of autozooids in pedunculate species of cyclostomes.
Cauda: Thread-like proximal gymnocyst of club-shaped cheilostome autozooid.
Condyle: One of a pair of oppositely placed tooth-like protuberances on which the operculum pivots in the orifice of ascophoran cheilostomes.
Connate: Describing groups of autozooids arranged in linear rows, with the erect, peristomial portions fused in rigid, comb-like series in some cyclostomes.
Costa: Modified spine overarching the frontal membrane in cribrimorph cheilostomes; usually united with neighbouring costae to form a frontal shield spinocyst.
Costate shield or Spinocyst: The frontal wall of cribrimorph ascophorines, formed from series of fused costae.
Cryptocyst: More or less horizontal calcareous lamina of the frontal interior wall in cheilostomes.
Distal: Pertaining to the side away from the ancestrula or origin of colony growth.
Ectooecium: Outer layer of ooecial wall.
Entooecium: Inner layer of ooecial wall.
Entosaccal cavity: That part of the body cavity of cyclostome autozooids enclosed by the membranous sac and the outer body wall; regarded as a pseudocoel.
Exterior wall: The outer body wall of the autozooid, including the cuticle and adjacent epithelium and calcified structures.
Extrazooidal: Structures not referable to a single zooid.
Fasciculate: Describing an arrangement of autozooids in which groups of erect peristomial portions are fused in bundles called fascicles.
Fenestra: Uncalcified area in the ectooecium through which the entooecium is visible.
Fenestrule: Open space in reticulate colony.
Fixed-walled: Skeletal organisational grade in cyclostomes in which the zooid has a calcified exterior frontal wall.
Free-walled: Skeletal organisational grade in cyclostomes in which the zooid lacks a calcified exterior frontal wall and retains hypostegal pseudocoelomic connection with neighbouring zooids over the distal ends of their interior walls.
Frontal: Pertaining to the orifice-bearing side of zooid or colony.
Frontal membrane: Uncalcified part of frontal body wall in cheilostomes.
Frontal shield: The calcified frontal surface of an ascophoran zooid.
Gonozooid: Zooid modified as an embryonic brood chamber.
Gymnocyst: Calcified frontal shield formed of exterior calcification in cheilostomes.
Heterozooid: Specialised zooid unable to feed.
Hypostegal coelom: An extension of the main coelom overlying the frontal shield in some ascophoran cheilostomes.
Hypostegal pseudocoelom: Body cavity in cyclostomes connecting neighbouring zooids over the distal ends of their interior walls.
Interior wall: Calcified internal walls or partitions not bounded by the zooid cuticle and overlain by epithelium and coelom or pseudocoel.
Internode: Solid branch between the elastic nodes of articulated colonies.
Interzooidal avicularium: One which extends to the basal surface of the colony, but is wedged between autozooids rather than replacing one of them.
Kenozooid: Heterozooid without a polypide or operculum/mandible.
Lophophore: The ring of tentacles surrounding the mouth of the zooid.
Lyrula: Median tooth, often anvil-shaped, on the proximal side of the orifice in some cheilostomes.
Mandible: Avicularian equivalent of the operculum of an autozooid, seldom calcified.
Manticule: Mound on the colony surface, indicating the position of an exhalent chimney.
Maternal zooid: The proximal reproductive zooid from which ova pass to an ovicell.
Mucro: A blunt or spinous elevation of the (usually proximal) lip of the orifice in some cheilostomes.
Nanozooid: Dwarf zooid containing reduced polypide in some cyclostomes.
Node: Elastic joint between the solid branches in articulated colonies.
Occlusor muscles: Muscles closing the operculum.
Ooeciopore: The opening of the gonozooid, through which larvae are released.
Ooeciostome: The tubular growth containing the ooeciopore.
Operculum: A generally uncalcified lamina, hinged or pivoting on condyles, which closes the zooidal orifice in cheilostomes, seldom calcified.
Opesia: The main opening in the skeleton of an anascan cheilostome zooid.
Oral: Pertaining to the orifice of a bryozoan zooid (not to the mouth).
Oral spine: Spines located around the distal edge of the orifice, often basally articulated.
Orifice: Opening in the zooid through which the lophophore is extended in cheilostomes.
Ovicell: The globular brood chamber of many cheilostomes.
Peristome: Elevated rim or tube surrounding the cheilostome orifice or cyclostome aperture.
Polymorph: Name applied to zooid types in colonies possessing more than one kind of zooid.
Polypide: Those organs and tissues in a bryozoan autozooid which undergo periodic replacement; i.e. the tentacles, tentacle sheath, alimentary canal, associated musculature and nerve ganglion.
Pore chamber: Small chambers developed basally around the perimeter of the zooid in some cheilostomes.
Poster: Part of the orifice in ascophoran cheilostomes proximal to the condyles and leading to the ascus.
Protoecium: The proximal, hemispherical portion of the cyclostome ancestrula derived directly from the metamorphosed larva.
Proximal: Pertaining to the side toward the ancestrula or origin of colony growth.
Pseudopore: Tissue filled pore in the calcification of the zooidal exterior wall in cyclostomes closed by the outer cuticle; or pore between the main (visceral) and hypostegal coelom in the frontal shield of some cheilostome zooids.
Pseudosinus: A notch or hole in the the peristome of some ascophoran cheilostomes.
Retractor muscles: Muscles arising from the proximal end of the zooid, inserted on the pharynx and the base of the lophophore, serving to withdraw the polypide.
Rosette-plate: Multiporous subcircular area in vertical walls of cheilostomes for the passage of mesenchymatous fibres between zooids.
Rostrum: Distal part of the avicularium occupied by the mandible.
Secondary orifice: In those cheilostome species with an immersed primary orifice, the outer opening of the peristome.
Sinus: Slit at proximal edge of orifice in some ascophoran cheilostomes.
Tatiform: A cheilostome ancestrula with a membranous frontal wall, usually surrounded by spines.
Umbo (pl. Umbones): A blunt prominence on the frontal shield or ovicell in some cheilostomes.
Vibraculum: Variety of avicularium in cheilostomes with an operculum in the form of a long seta slung between condyles.
Vicarious avicularium: One that replaces an autozooid in a series and is approximately the same size.
Zoarium: Calcified skeleton of the colony.
Zooeciule: Small cheilostome zooid with orifice but not all of the parts of an autozooid.
Zooecium (pl. Zooecia): Calcified skeleton of a bryozoan zooid.
Zooid: Single bryozoan individual.