Polikey glossary. Adapted from Glasby, C.J., Fauchald, K. & Hutchings, P.A. (2000). Glossary. Pp. 401412 in Beesley, P.L., Ross, G.J.B. & Glasby, C.J. (eds). Polychaetes & Allies: the Southern Synthesis. Fauna of Australia. Vol. 4A Polychaeta, Myzostomida, Pogonophora, Echiura, Sipuncula. CSIRO Publishing : Melbourne xii + 465 pp.
See also POLiKEY ABRS site.
A | B | C | D | E | F | G | H | I-J | K | L | M | N | O | P | Q | R | S | T | U-V | W-Z
abdomen:
body region posterior to the thorax, sometimes followed by a tail.abyssal:
oceanic waters between depths of 4000 m and 6000 m.achaetigerous:
see achaetous.achaetous:
without chaetae.acicula, aciculae:
a stout supportive chaeta found internally in projecting parapodial rami.acicular chaeta:
stout, projecting chaeta.acicular muscle:
see oblique muscle.acoelomate:
pertaining to animals lacking a coelom.aileron:
accessory jaw plate in Glyceridae.anal cirrus, anal cirri:
see pygidial cirrusanal plaque:
depressed (or sunken) plate-like pygidium of some maldanids and other polychaetes.annulated:
ringed or marked with grooves delineating segments.antenna, antennae:
sensory projection arising from the dorsal, lateral or frontal surface of the prostomium.antennular auricle:
= auricule.antennular membrane:
see cephalic veil.anterior gut:
see foregut.apical tooth:
see primary tooth.apodous:
segments without parapodia.apomorphy:
an advanced or derived feature; compare plesiomorphy.arborescent:
branching like a tree.arenicoliform:
body forms that are swollen anteriorly and tapered posteriorly.arista, aristae:
fine hair-like or bristle-like structure.aristate chaeta:
simple chaeta with smooth shaft and a tuft of hairs or a single spine distally.article:
demarcated sections of chaetae or cirri separated by joints.articulate:
jointed, as in antennae, tentacular cirri, palps and dorsal cirri.asetigerous:
see achaetigerous.atoke:
non-sexual, unmodified state of an individual in some polychaete groups; pertaining to species which undergo epitoky.auricule:
paired ear-shaped processes at the base of an antenna (ceratophore) characteristic of some sigalionids.autapomorphy:
a derived character unique to a particular taxon.avicular:
beaked; shaped like a birds head.axial:
pertaining to, or situated on the axis.basal lappet:
= auricule.benthic:
pertaining to the sea floor.benthonic:
pertaining to the benthon or community of organisms that inhabit the sea floor.biarticulate:
with two joints; pertaining to antennae, tentacular cirri, palps and dorsal cirri.bidentate chaeta:
chaeta with two teeth distally.bifid:
distally split in two; usually pertaining to chaetae.bifurcate chaeta:
simple chaeta with two prongs.bilabiate:
with two lips, usually about parapodial lobes.bilimbate chaeta:
simple chaeta with two wings; see limbate.bipectinate:
branching like a feather from a central axis; similar to pinnate, but branches coarser.bipinnate:
a structure that is pinnate for both its primary and secondary divisions; see pinnate.biramous parapodium:
parapodium with two branches, a notopodium and a neuropodium.blade:
a distal, flattened portion of a compound or simple chaeta.boss:
small projection or knob-like process in compound and simple chaetae.brain:
ganglionic mass situated at least in part in the prostomium.branchia, branchiae:
extension of the body wall with a loop of the vascular system; usually well equipped with capillary blood-vessels.branchial crown:
see radiolar crown.branchiole:
see radiole.bristle:
see chaeta.brush-tipped chaeta:
see penicillate chaeta.buccal cavity:
mouth cavity.buccal cirri:
cirri in or around the mouth; sensory function rather than feeding (cf. buccal tentacles).buccal organ:
anterior part of alimentary canal derived from larval stomodaeum, comprising a complex set of folds, musculature and glands; see pharynx, proboscis; see also ventral buccal organ.buccal tentacles:
elongate, grooved, usually ciliated appendages in or around the mouth; palpal derivatives.bulbus:
knob-like structure swollen in appearance.caecum, caeca:
blind sac arising from the alimentary canal; applied also to other organ systems, such as nephridia.calicinate:
like the calyx of a flower.camerate:
divided into chambers.canaliculate:
with a (fine) canal or groove.capillary chaeta:
slender, often long, chaeta tapering to a fine point.capillary, capillaries:
see capillary chaeta.caruncle:
projection from the posterior end of the prostomium carrying nuchal organs.cauda:
see pygidium.caudad:
towards the tail.caudal plaque:
flattened pygidium.cephalad:
towards the head.cephalic cage:
structure formed from long, forwardly directed chaetae more or less enclosing the head.cephalic keel:
median ridge on the prostomium or head, as in some Maldanidae.cephalic peaks:
see prostomial peaks.cephalic plaque:
see cephalic plate.cephalic plate:
plate-like antero-dorsal surface of the head region in some Maldanidae and Pectinariidae.cephalic rim:
flange encircling the head in some polychaetes.cephalic veil:
Hood-like membrane between the paleae and the buccal tentacles in Pectinariidae. see also tentacular membrane.cephalisation:
incorporation of anterior, usually modified cephalised segments, with the head (prostomium/peristomium).cephalon:
see head.ceratophore:
basal part of an antenna.ceratostyle:
distal part of an antenna.chaeta, chaetae:
a chitinous bristle protruding from a pocket in the body wall.chaetal gland:
(= chaetal sac) a series of follicles in the parapodium that secrete the support rod, the hook in use, and a varying number of replacement hooks.chaetal inversion:
presence of uncini on the notopodia rather than the more usual position on the neuropodia.chaetiger:
segment bearing chaetae.chaetigerous lobe:
that projection or part of the notopodium or neuropodium which bears the chaetae.chaetoblast:
cell which forms, together with follicle cell, a chaeta.chevron:
V-shaped chitinised jaw piece at the base of the eversible pharynx in some Goniadidae.chromaphil gland:
see chromatophil gland.chromatophil gland:
densely staining gland in the ventral pinnule of Tomopteris; see also rosette gland.chromatophore:
special cell or group of cells carrying pigment.ciliophore:
distinct area or epidermal patch covered with cilia.circular muscle:
muscle layer encircling the body between the epidermis and longitudinal muscle layer.circumoesophageal connective:
tracts of nervous tissue passing down from the brain on either side of the foregut and connecting to the ventral nerve cord.circumoral tentacles:
see tentacles.cirriform:
slender and cylindrical.cirrophore:
basal projection on which a cirrus is mounted.cirrostyle:
distal part of a cirrus or tentacle.cirrus, cirri:
sensory appendage; usually slender and cylindrical.clade:
a complete set of taxa with a common ancestor.cladistics:
classification of taxa based on lines of evolutionary descent, and, in principle, recognising only clades.clavate:
club-shaped.coelom, coelomate:
body cavity with peritoneal lining; formed in embryonic mesoderm; characteristic of almost all bilateral animals; lined with epithelium termed the peritoneum.coelomocytes:
amoebocytes present in the coelom.coelomoduct:
a tubule derived from coelomic tissue, connecting the coelom with the external environment; often combined with nephridium and termed nephromixia.coelomostome:
funnel at the inner end of a coelomoduct.cold seep:
emergence of fluid from sedimentary rocks under pressure, such as in regions of continental subduction; may comprise hydrocarbons, such as methane, or water, bearing salts such as sulphides.collar:
anterior encircling fold or flap, such as that covering the base of the radiolar crown in Sabellidae and Serpulidae.comb chaeta:
simple chaeta with a comb-like arrangement of teeth on the distal end; present in some Eunicida.commensalism:
an association between two species that live together, which benefits individuals of one species without harming those of the other.commissure:
a transverse band of neural tissue linking paired ventral nerves or longitudinal nerve tracks; one of four main tracts of nervous tissue passing through the brain.companion chaetae:
small, simple chaetae, accompanying, or alternating with larger chaetae, usually hooks of some kind.compensatory vessel:
see contractile vessel.composite chaeta:
see compound chaeta.compound chaeta:
chaeta having a terminal portion which articulates with the shaft.compressed
: flattened in one plane, usually laterally.consecutive hermaphroditism:
change from one sex to another in an individual; may be protandrous, protogynous, or bi-directional.copragogue:
see faecal groove.cordate, cordiform:
heart-shaped.cristate:
bearing a ridge or crest.crotchet:
see hook.crown:
a bilaterally symmetrical branched structure in some polychaetes formed by prostomial palps.ctenidium, ctenidia:
a finger-shaped or flattened structure presumed to have a respiratory function.ctenognath:
arrangement of complex jaw apparatus in which the jaws comprise relatively large basal maxillae and symmetrically arranged rows of numerous anterior denticles in longitudinal series without carriers.cuticular shield:
stiff, iron-impregnated shield on the posterior venter of Sternaspidae; see sternal shield.cuticle:
thin, non-cellular protective layer produced by and overlying the epidermis in many invertebrate groups; consists mainly of scleroprotein (not chitin).cutis:
see dermis.cutting plate:
distal part of eunicean mandible.deciduous:
pertaining to structures easily autotomised, or shed by the animal as a defensive reaction.dendrites:
branching cytoplasmic processes of sensory cells.dental formula:
notation showing the distribution of teeth on the crest of a hook or uncinus.dentate:
toothed.denticle:
a minute tooth.denticulate:
finely toothed.depressed:
flattened, usually dorso-ventrally.dermis:
layer of skin underlying the epidermis; comprises connective tissue and a range of other cell types, such as pigment and nerve cells.detritus:
particles of organic origin.diagonal muscle:
obliquely aligned dorso-ventral muscle in the body wall (cf. oblique muscle).digitiform:
finger-shaped.dioecious:
(= gonochorism, gonochoric) pertaining species, in which individuals are either male or female throughout life.direct developers:
embryos that develop completely into juveniles without intermediate larval stages.distal:
that part of a structure towards the end.diverticulum, diverticula:
blind tube(s) or sac-like extension(s) of the lumen of an organ.dorsal blood vessel:
longitudinal vessel which carries blood forward through the body; situated above the gut.dorsal cirrus:
cirrus normally situated on the upper edge of the notopodium.dorsal cirrus organ:
sensory organ, with numerous long cilia at the ventral base of the dorsal cirrus in Eunicida.dorsum:
dorsal surface of body.dorso-ventral muscle:
see diagonal muscle.echinulate:
prickly.elytrigerous segment:
polychaete segment bearing a scale.elytron, elytra:
dorsal scales found in the scale-worms; homologous with the dorsal cirrostyles.elytrophore:
cirrophore carrying an elytron, as in scale-worms.endoderm:
the innermost layer of germ cells developed during gastrulation.endothelium:
epithelial cells lining the inner wall of the circulatory system.entire margin:
smooth edged; lacking papillae, teeth or other projections.enteronephridia:
blind ciliated canals opening into the stomach.epidermis:
outer layer of the skin, usually one cell thick in invertebrates; derived from ectoderm.epigamy:
structural modification of an entire adult individual polychaete into a reproductive state or epitoke (cf. schizogamy).epitoke:
an individual polychaete morphologically modified to leave the bottom to reproduce (epitoky); epigamous epitokes result from the transformation of an atoke to the epitoke; schizogamous epitokes arise by modification and separation from the posterior end of the worm. Often swarms of epitokes appear.eversible pharynx:
part of pharynx being capable of being extended by turning the inner part outwards.eversible proboscis:
see eversible pharynx.eye:
light receptive organ which usually occurs on the prostomium but may occur elsewhere on the body or appendages.eyespot:
light sensitive structure in several polychaete groups. See ocellus.facial tubercle:
projecting ridge or lobe on the upper lip of certain polychaetes, especially scale-worms.faecal groove:
groove, on the posterior region of a tubicolous polychaete, along which the faecal pellets pass before being voided from the tube.falcate chaeta:
distally curved, usually blunt chaeta.falciform:
hook-shaped.falciger:
compound chaeta with a stout, hooked appendage or blade.fang:
a major tooth-like projection of an uncinus, hook or maxillary plate.fascicle:
a small bundle, of tissue, such as muscle or nerve fibres, or structures, such as chaetae.felt:
matted thin chaetae produced by the notopodia in some species of scale-worms.fenestrated:
with one or more window-like openings; used to refer to the ladder-like arrangement of transparent compartments in the shaft of some polychaete chaetae.fibrocyte:
connecting tissue cell, synonymous with, or derived from a fibroblast.filamentous:
shaped like a fine thread.filiform:
slender and thread-like.fimbricated:
having flattened, leaf-like processes.flail chaeta:
abruptly tapering and distally bent capillary chaeta of some orbiniids.flanged chaeta:
see limbate or bilimbate chaetae.foliaceous:
thin and leaf-like.foot:
see parapodium.foregut:
anterior, cuticle-lined part of the alimentary canal including the pharynx and oesophagus; derived from the ectoderm; see also stomodaeum.forked chaeta:
see furcate chaeta.formalin:
a solution of formaldehyde in water, used for fixing tissues.frontal palps:
anterior, sensory appendages of prostomium in Onuphidae.frontal peaks:
see prostomial peaks.furcate chaeta:
short (usually), bifurcated simple chaeta.fusiform:
cigar- or spindle-shaped.geniculate chaeta:
simple chaeta formed like a bent knee.genital hook:
modified notopodial chaeta used in mating in some Capitellidae.genital papilla:
projection on which a reproductive duct opens.genital pore:
modified nephridial opening.genital pouch:
a pocket-like skin fold between neuropodia in some Spionidae.giant fibre:
enlarged fibre in the nerve cord capable of very rapid conduction of nerve impulses.gill:
see branchia.gizzard:
muscular, barrel-shaped part of the foregut behind the pharynx in some Spionidae.glabrous:
smooth, glistening.gonads:
paired segmented peritoneal organs producing eggs or sperm.gonochorism, gonochoric:
(= dioecious) individuals are either male or female throughout life.gonoduct:
see coelomoduct; see also nephridia in echiurans and sipunculans.guard:
paired delicate chitinous sheaths protecting the tip of some chaetae.gular membrane:
a muscularised septum between two successive anterior segments; divides the coelom into anterior and posterior parts.gut sinus:
thin-walled open chamber of circulatory system around the gut.gynandry:
development of female reproductive system before male system in consecutive hermaphrodites.hadal:
oceanic depths exceeding 6000 m.haemerythrin:
respiratory pigment in sipunculans; in different taxa may comprise two, three or eight units of polypeptide attached to two Fe ions.harpoon chaeta:
stout pointed chaeta with recurved barbs near the tip.hastate:
shaped like the blade of a spear.head:
collective term used for a structure formed by the fusion of peristomium, prostomium and, in many instances, one or more cephalised segments.hemigomph:
compound chaeta with articulation which re-aligns the tip at close to a right angle to its long axis.hermaphroditism:
presence of functional male and female reproductive systems in an individual, at the same time (simultaneous hermaphroditism) or sequentially (consecutive hermaphroditism).heterogomph:
compound chaeta with articulation which clearly re-aligns the tip obliquely to the long axis of the shaft.hindgut:
posterior-most region of the alimentary canal, usually short; ectodermally derived.hirsute:
hairy, often with reference to chaetae.hispid:
minutely hairy; furry, often with reference to chaetae.homogomph:
compound chaeta with articulation which re-aligns the tip at a right angle to its long axis.homologues:
structures of common evolutionary origins, irrespective of functionality, derived from the same structure in the common ancestor.homology:
fundamental similarity in different organisms as a result of their common ancestry.homoplasy:
correspondence in morphology of different organisms as a result of evolutionary convergence or parallel evolution.hood:
a delicate chitinous envelope with a single opening, covering the apex of hooks or other chaetae (see also guards).hook:
stout-shafted, unjointed, distally-curved chaeta with or without teeth near the apex.hyaline:
transparent, glassy.hyaline gland:
gland in the pinnules of certain species of Tomopteris; usually translucent, sometimes with a yellow spot in the centre.hydrostatic skeleton:
controlled support provided by muscular pressure on body fluids, especially the major venous sinuses; used to modify body or organ shape.hydrothermal vent:
site of emerging, often highly sulphidic hot water, after it has circulated through new crustal rocks at spreading ridges in the deep-sea floor.imbricated:
overlapping like tiles.intermediate cirrus:
cirriform structure attached to the body wall between the notopodium and neuropodium.inter-ramal cirrus:
a cirriform structure attached to the notopodium, projecting into the space between the notopodium and the neuropodium.intersegmental:
between segments.intestine:
absorptive part of the midgut, usually a straight tube.iteroparity:
breeding in more than one season, often at regular intervals.J
jaw formula:
see maxillary formula.jaws:
hardened feeding or grasping apparatus with opposable units situated in the eversible pharynx.jointed chaeta:
see compound chaeta.labial palps:
ventral sensory appendages of prostomium in Eunicida.labidognath:
arrangement of complex jaw apparatus in which the larger jaw pieces are located in a pocket with the smaller pieces arranged in semi-circles at the anterior end.lacuna(e):
space(s) or cavity (cavities), usually with reference to those in tissues.lamella, lamellae:
fleshy, flattened or plate-like structure(s).lamellate:
plate-like, usually referring to a lobe.lanceolate:
pointed and shaped like a lance.lappet:
lobe or flap-like projection.lateral caecum:
blind sac arising laterally from the alimentary canal.lateral lappet:
lobe or flap-like projection on anterior segments in Terebellidae.lateral organ:
small, rounded inter-ramal elevations with stiff projecting hairs; see also dorsal cirrus organ, stereocilia.lateral shield:
glandular area on the lateral venter of thoracic segments in Polycirrus; cf. ventral pads.lecithotrophy:
form of development in which larvae generally do not feed, relying on yolk in egg.ligule:
compressed conical lobe of a parapodium; cf. lobe.limbate chaeta:
simple chaeta with a flattened wing projecting from one side along much of its distal half; see also bilimbate.lobe:
conical process of a parapodium; cf. ligule.long-handled uncinus:
uncinus with a long, rod-like basal extension.longitudinal muscle:
muscle layer running parallel to the long axis of the body, between the circular muscle and the peritoneum; usually arranged in two dorso-lateral and two ventro-lateral bands.lyre chaeta, lyrate chaeta:
delicate forked-type chaeta. See furcate chaeta.macrobenthos:
benthic invertebrate fraction retained in a 1 mm sieve.macrognaths:
paired lateral jaw pieces of Goniadidae.macrotubercle:
see tubercle.main fang:
see fang, see also primary tooth.mammillate:
pertaining to nipple-like process.mammiliform:
breast-shaped.mandible:
ventral jaw plate in Eunicida.maxilla:
dorsal jaw plate in Eunicida.maxillary carrier:
posterior support for the maxillae.maxillary formula:
summary of the number and arrangement of maxillary plates and teeth in Eunicida.maxillary ring:
distal part of the everted pharynx in Nereididae.medial:
the mid-line regions of the body.median:
in the mid-line.meiobenthos:
benthic invertebrate fraction that passes through a 1 mm sieve but is retained on a 42 m m sieve.metamerism, metameres:
segmentation of the body into a series of similar units, termed metameres.metanephridia:
type of nephridia in which the coelomic end has an open funnelmetastomium:
rarely used term covering the segmented body between the prostomium/peristomium and the pygidium, but including neither.micrognaths:
numerous small jaw pieces arranged in a ring in the pharynx of Goniadidae.microtubercle:
see tubercle.microvilli:
minute, very slender (>0.01 mm diameter) extensions of surface of epithelial cells.midgut:
central part of the alimentary canal comprising the stomach, when present, and the intestine; endodermal origin.mitraria larva:
larva of oweniid polychaete; swim by ciliary action of an umbrella-like structure.moniliform:
beaded or beadlike.monophyly, monophyletic:
pertaining to a group of taxa comprising a common ancestor and all its descendants.mouth:
anterior opening of the alimentary canal; usually anterior opening of fully everted pharynx.mucro:
a sharp point or tip on an abruptly tapering structure.mucronate:
sharply pointed.multiarticulate:
with three or more joints.multidigitate:
with many finger-like lobes or projections.mutualism:
symbiotic association between two members of different species which benefits both organisms.myo-epithelium:
epidermal layer which includes contractile epithelial cells.natatory:
swimming.nectochaete:
developmental stage of an annelid following metatrochophore (up to 20 or so chaetigers); ciliation is reduced and parapodia function in locomotion.nematoform:
worm-like.nephridial papilla:
projection on which the excretory organ opens.nephridiopore:
the external opening of a metanephridium; see also nephridium.nephridium, nephridia:
excretory organ(s) opening to the exterior via a duct and a nephridiopore; fluid enters the internal end of the more primitive protonephridium through selenocytes; fluid enters the internal end of metanephridium though an open, ciliated funnel termed a nephrostome.nephromixia:
combinations of coelomoduct and nephridium termed protonephromixium, metanephromixium and mixonephridium; in protonephromixium, mesodermal components are fused with a protonephridial canal; in a metanephromixium, the mesodermal funnel has become joined with an open nephrostome; in a mixonephridium the coelomic end of the nephridium is completely fused with the funnel of a coelomoduct.nephrostome:
ciliated funnel of the coelomic opening of a metanephridium; see also nephridium.nerve cord:
ventral, segmentally ganglionated nerve trunk passing along the length of the body.neuroacicula:
acicula of the neuropodium.neurochaeta:
chaeta of a neuropodium.neurocirrus:
see ventral cirrus.neurofibrils:
fine proteinaceous longitudinal fibres forming a network within the nerve cell body, axons and dendrites.neuropodium, neuropodia:
ventral branch or ramus of a parapodium.neuroseta:
see neurochaeta.neurotroch:
longitudinal ventral band of cilia in trochophore.notoacicula:
acicula of the notopodium.notochaeta, notochaetae:
chaeta of a notopodium.notocirrus:
see dorsal cirrus.notopodium, notopodia:
dorsal branch or ramus of a parapodium.notoseta:
see notochaeta.nototroch:
regularly scattered dorsal ciliary bands on body of trochophore larva.nuchal:
pertaining to the neck.nuchal cirrus:
see nuchal papilla.nuchal epaulettes:
see nuchal organs.nuchal organs:
paired chemosensory structures situated postero-laterally on the prostomium, developed variously as pits, grooves, epaulettes, or elongated ridges.nuchal papilla:
papilla found on the posterior margin of the prostomium of some Phyllodocidae and Spionidae.oblique muscle:
muscle attached to the aciculae and chaetae; cf. diagonal muscle.occipital:
pertaining to the postero-dorsal part of the prostomium.occipital collar:
a prominent fold immediately overlapping the posterior part of the prostomium.occipital fold:
see occipital collar.occipital lappet:
see occipital collar.occipital papilla:
see nuchal papilla.ocellus, ocelli:
small eye spot(s).ocular:
pertaining to the eye.ocular peduncle:
see ommatophore.oesophageal caecum:
blind sac arising from the oesophagus.oesophagus:
posterior part of the foregut connecting the pharynx to the intestine; includes the gizzard or proventricle, and caeca when present.ommatidium:
functional optic unit of the compound eyes on the tentacular crown of some sabellidans.ommatophore:
projecting structure supporting the eyes, especially in scale-worms.oocyte:
female reproductive cell; diploid primary oocyte forms, through meiosis during oogenesis, a haploid secondary oocyte which divides to form an ovum.oogenesis:
formation and development of female gametes from diploid oogonia to mature, haploid ova.oogonia:
diploid precursor of primary oocytes, derived by mitosis during oogenesis.operculum, opercula:
plug at the anterior end of some tube-dwellers which blocks the tube opening when the worm retracts.oral cavity:
mouth cavity.oral filaments:
see tentacles.oral ring:
proximal part of the everted pharynx in Nereididae.otocysts:
see statocysts.oviduct:
tube conducting eggs or oocytes to exterior.oviparous:
pertaining to deposition of eggs which develop completely and hatch externally.ovoid:
shaped like a birds egg.palea, paleae:
broad, usually flattened chaetae, often with a metallic sheen.palmate:
resembling the fronds of a palm.palp, palpi:
one of a set of paired, elongate or cushion-like structures arising from the sides of the head; anteroventral and sensory in many errant polychaetes; placed postero-dorsally and used in feeding in spioniform polychaetes.palpode:
tapering anterior projection of the prostomium.palpophore:
basal part of a jointed palp.palpostyle:
distal part of a jointed palp.papilla, papillae:
a small, nipple-like projection.papillose:
bearing numerous small, rounded to conical projections.paragnath formula:
summary of number and arrangement of denticles on the pharynx in Nereididae.paragnath:
sclerotinised denticle on the pharynx in Nereididae.paraphyly, paraphyletic:
pertaining to a group of taxa comprising a common ancestor but not all of its descendants; see polyphyly and monophyly.parapodial trunk:
proximal, undivided part of an elongate parapodium.parapodium, parapodia:
one of the two fleshy lateral projections from a body segment, usually bearing chaetae and sometimes greatly reduced.paratomy:
see schizotomy.parenchyma:
mesodermal tissue surrounding, and filling spaces between organs, muscles and other tissues.pectinate:
comb-like; with series of projections arranged like the teeth of a comb.pectinate chaeta:
see comb chaeta.pedicel:
a short stalk.penicillate chaeta:
simple chaeta with a brush-like tip.peristalsis:
rhythmic, directional wave of muscular contraction in a vessel or tube.peristome:
see peristomium.peristomial cirri:
paired, elongated cirri on the peristomium.peristomial ring:
annulus associated with the peristomium.peristomium:
presegmental region of the body that lies between the prostomium and the first segment; in many polychaetes the peristomium only forms an area around the mouth.peritoneum:
serous membrane lining the coelomic cavity.pharyngeal organ:
see buccal organ.pharynx, pharynges:
anterior muscular part of the foregut, including the eversible proboscis.pilose:
covered with very short hairs giving a velvety appearance.pinnate:
feather-like; two rows of pinnules branching from a central axis (cf. bipinnate; bipectinate).pinnules:
small side branches, in a feather-shaped process, such as the radiole in Sabellidae and Serpulidae.piriform:
see pyriform.planktotrophic:
larval development in which eggs with little yolk hatch as small, free-swimming trochophores which feed on algae in the water column.platelet:
syncytial mass of spermatozoa.plesiomorphy:
primitive retained character; compare apomorphy.plumose:
resembling down; hairy.polyphyly:
pertaining to a group comprising two or more taxa derived from distinct lineages.polytelic:
pertaining to individuals or species in which adults survive to spawn during two or more breeding seasons.polytomy, polytomous:
incompletely resolved node on tree of relationships, where several branches originate together.polytypic:
pertaining to a genus with more than one species, a family with more than one genus, etc.postchaetal:
posterior to the chaetae; used in relation to parapodial lobes or ligules.postsetal:
see postchaetal.prechaetal:
anterior to the chaetae, used in relation to parapodial lobes or ligules.presetal:
see prechaetal.primary tooth:
larger distal tooth of an unequally bidentate chaeta.prionognath:
arrangement of complex jaw apparatus in which the generally similar jaw-pieces are located in two rows on longitudinal ridges.proboscis, proboscides:
eversible, non-muscular part of the buccal organ (strictly); often used interchangeably with pharynx.prostomial keel:
see cephalic keel.prostomial peaks:
antero-lateral projections, often chitinised, of the prostomium in some scale-worms.prostomium, prostomia:
anteriormost, presegmental and pretrochal region of the body, sometimes bearing eyes and antennae; may not be externally recognisable.protandry, protandrous:
sequence of sexual stages, from a functional male stage to a hermaphroditic and/or a functional female stage in consecutive hermaphrodites.protogyny, protogynous:
sequence from a functional female stage to a hermaphroditic and/or a functional male stage in consecutive hermaphrodites.protonephridia:
type of nephridia in which the coelomic end is closedProtostomia, protostomes:
primary grouping in bilateral animals characterised by determinate cleavage, in which the fate of cells is pre-determined; found in platyhelminthes, annelids, molluscs and arthropods.prototroch:
primary, anterior-most transverse ring of locomotory cilia on the body of the trochophore larva, lying anterior to the mouth.proventricle:
muscularised region of the anterior digestive tract occurring posterior to the pharynx; with muscle fibres arranged radially; characteristic of the Syllidae.proventriculus:
see proventricle.proximal:
part of a structure nearer to the base or main body.psammophilic:
pertaining to sand-dwelling organisms.pseudocompound:
pertaining to compound chaeta in which the articulation is incomplete.pseudocopulation:
a form of sperm transfer in some polychaete groups involving spermatophores, spermatozeugmata, or free spermatozoa.pseudofaeces:
sediment particles transported upwards from feeding depths by a polychaete worm and ejected from the tube; texturally indistinguishable from faeces.pseudojointed:
see pseudocompound.pygidial:
pertaining to the anal region or pygidium.pygidial cirrus:
cirrus projecting from the pygidium.pygidium:
post-segmental terminal part of the body surrounding the anus.pyriform:
with a broad bulbous base and tapered tip; pear- or onion-shaped.pyriform glands:
multicellular epidermal glands which secrete chitin and mucopolysaccharides to form the pogonophoran (Siboglinidae) tube.radiole, radii:
primary branch in the tentacular crown in Sabellidae and Serpulidae.radiolar crown:
a radiolar crown is a feather-like feeding and respiratory structure comprising radioles which are basally attached to a lobe surrounding the mouth; in Serpulidae and Sabellidae only. See also branchial crown.ramose:
branched.ramus, rami:
branch, in relation to the dorsal or ventral branch of a parapodium.raptorial:
feeding mode involving snatching, seizing or tearing apart.rectum:
see hindgut.reniform:
kidney-shaped.reticulate:
pattern or structure forming a network or mesh.retort organ:
club-shaped gland opening into the buccal cavity in Typhloscolecidae.rhabdomere:
photoreceptive element of a compound eye.ringent chaeta:
simple, subdistally expanded chaeta with a narrow slit which is internally crenulated or serrated; in Euphrosinidae.rosette gland:
yellowish star-shaped glands in the pinnules of some species of Tomopteris; see also chromatophil gland.rosette:
syncytial mass of spermatozoa.rostrum:
enlarged first tooth or fang of a chaeta, usually a hook or uncinus.rugose:
roughened, lumpy.sabre chaetae, sabre-like chaetae:
chaeta with a broad curved blade.scale:
see elytron.scaphe:
flattened caudal end in Pectinariidae; see also pygidium.schizogamous epitoke:
see epitoke.schizogamy:
structural modification of the adult involving the budding off of sexual individuals; see also stolons, epigamy.schizotomy:
asexual reproduction involving two forms of subdivision of the body and regeneration of the missing parts; in paratomy, a recognisable complete individual forms and then separates from the 'parent' stock; in architomy, the body breaks or fragments without any prior cephalisation.scleroprotein:
one of a group of proteins incorporated into skeletal, connective or epidermal structure.sclerotinised:
pertaining to the hardening of the exoskeleton with the quinone-tanned protein sclerotin.secondary tooth:
smaller, proximal tooth of an unequally bidentate chaeta.segment:
one of the serially repeated units comprising the trunk; often separated internally by septa.segmental organs:
organs occurring in segmental arrangement; used specifically with reference to nephridia and nephridial ducts.selenocyte:
blind-ending region at the coelomic end of the metanephridium; see also nephridium.semelparity:
death following a single reproductive season.sensory buds:
epithelial sensory/secretory structures on antennae and cirri.septum, septa:
structural partition(s) or division(s) between two visceral regions, within a haemocoel, or separating two cavities or tissue masses.sesquigomph:
see hemigomph (articulation).sesquiramous parapodium:
see sub-biramous parapodium.sessile:
pertaining to organisms attached to or situated directly on the substratum; without a stalk.seta, setae:
see chaeta, chaetae.setal:
see chaetal.setiger:
see chaetiger.setigerous:
pertaining to setae.setigerous lobe:
see chaetigerous lobe.shaft:
proximal part of a compound or simple chaeta; or proximal part of a eunicean mandible.sheath:
hyaline envelope covering a capillary chaeta.short-handled uncinus:
uncinus without a long basal extension.sickle chaeta:
simple chaeta with a sickle-shaped blade in some Spirorbinae.simple chaeta:
unjointed chaeta, includes hair-like (capillary) and robust (spines) types.simultaneous hermaphroditism:
presence of functional male and female reproductive systems in an individual at the same time.solenocytes:
terminal cells at the internal end of a protonephridium; responsible for filtering waste products from the coelomic fluid.spatulate, spathulate:
simple chaeta with a broadly expanded distal margin; like a spatula; spoon-shaped.spermathecae:
seminal receptacles.spermatid:
haploid, immature precursor of spermatozoon; derived from secondary spermatocyte.spermatogenesis:
process of sperm formation from diploid primordial spermatogonia to haploid spermatozoa.spermatogonia:
the earliest germ cells in the spermatogenic sequence.spermatophores:
bundles of spermatozoa, all enclosed by a sheath or capsule isolating them from the surrounding environment; see also spermatozeugmata.spermatozeugmata:
bundles of spermatozoa which are not surrounded by an external covering; may resemble bundles of late spermatids; see also spermatophores.spindle-shaped:
shaped like a cigar with pointed ends.spine:
a thick acicular or spear-shaped chaeta; may be straight or slightly curved.spiniger, spinigerous chaeta:
compound chaeta tapering distally to a fine point.spinning gland:
gland secreting tube-forming material (threads) present in parapodia of certain scale-worms.spinous pocket:
enlarged, pocket-like serration along the margin of the chaetae of some scale-worms.spinule:
a small spine.spinulose:
bearing small spines.squamous epithelium:
epidermal layer of flattened, scale-like cells.statocysts:
paired epithelial organs at the base of the tentacular crown in sabellids that function in equilibrium and orientation.stem cells:
undifferentiated adult or embryonic cell capable of unlimited division and of giving rise to one or more cell types.stereocilia:
inter-ramal sensory cilia; see also dorsal cirrus organ, lateral organ.sternal shield:
modification of the last segments forming a ventral plate in Sternaspidae; see also cuticular shield.stolon:
secondary individual formed by budding, usually from the posterior end, or elsewhere on the body.stolonisation:
form of asexual reproduction involving the formation of stolons.stomach:
glandular and/or muscular region of the midgut of most sedentary polychaetes.stomodaeum, stomadeum:
anterior part of the embryonic alimentary canal formed as an invagination of the ectoderm; see also foregut.striae:
fine parallel marks or lines.striated:
with striae.stylet:
a small pointed tooth-like structure.stylode:
finger-like projection associated with a parapodium, usually small and distinctly longer than wide.sub-biramous parapodium:
parapodium with a well-developed neuropodium and reduced notopodium.suboesophageal ganglion:
nerve centre at the junction of the circumoesophageal connectives and the ventral nerve cord.subterminal:
close to the apex of a structure.subulate:
awl-shaped.subuluncinus, subuluncini:
chaeta with a stout shaft tapering to a slender tip; intermediate between a capillary and an uncinus; see also aristate.symbiont:
participant in a mutualistic, commensal or parasitic relationship.symplesiomorphy:
primitive retained character shared by two or more taxa; compare synapomorphy.synapomorphy:
derived character shared by two or more taxa.synapse:
junction between two nerve cells or a nerve cell with another cell type such as muscle.tentacles:
general term for the long, paired or multiple food-gathering appendages; most are grooved and/or have a longitudinal row of cilia; see also buccal cirri, buccal tentacles, oral filaments.tentacular cirri:
dorsal and/or ventral cirri of parapodia of cephalised segments; often more elongate than those of more posterior parapodia; confused in the literature with peristomial cirri.tentacular crown:
array of elongated, longitudinally-grooved appendages on the head in Terebellida; used for feeding.tentacular membrane:
thin fold or hood extending from prostomium and bearing tentacles, often on its margin.tentacular formula:
notation indicating the arrangement of the tentacular cirri and chaetae; originally used for Phyllodocidae and Alciopidae, now also extended to other families.tentaculophore:
basal projection on which a tentacle is mounted.terminal tooth:
see primary tooth.tessellated:
pertaining to a surface with a network of grooves like a tiled wall.thoracic membrane:
thin fold extending from the dorsal part of the collar to the ventral side of the posterior thorax in most Serpulidae.thorax:
anterior region of the trunk in some polychaetes.tine:
prong of a forked-type chaeta; may be smooth or fringed with hairstorus, tori:
welt or ridge-like parapodial ramus, often with hooks or uncini.trabeculae:
struts of tissue forming a supportive or bracing framework within a space.trepan:
sclerotinised ring of teeth in the anterior pharynx of Syllidae.trichogenic cells:
cells which secrete fine hair-like threads.tridentate:
with three teeth.trochophore:
early, ciliated, free-swimming, planktonic larval stage before segment proliferation beginstruncate:
pertaining to a structure that ends abruptly, without tapering.trunk:
the segmented region of the body between the peristomium and pygidium.tubercle:
knob-like protruberance; often referring to a large (macrotubercle) or small (microtubercle) projection on the elytron of some Polynoidae.unciniger:
segment carrying uncini.uncinigerous:
bearing uncini.uncinus, uncini:
deeply embedded short beak-like chaeta with a heavily dentate crest and wekly devleloped (or no) shaft; usually arranged in rows transverse to the long axis of the animal; see also long-handled uncinus.unidentate:
distally entire; often pertaining to chaetae.uniramous parapodium:
parapodium in which one ramus, most frequently the notopodium, is absent.unjointed chaeta:
see simple chaeta.urite:
projection from the pygidium.V
venter, ventrum:
the lower body surface.ventral blood vessel:
longitudinal vessel which carries blood posteriorly through the body; situated beneath the gut.ventral buccal organ:
variable, often complex set of folds, musculature and glands present on the ventral side of many polychaetes; see pharynx.ventral cirrus:
cirrus normally situated on the lower edge of the neuropodium.ventral groove:
longitudinal mid-ventral furrow.ventral muscle bulb:
see pharynx.ventral pads:
glandular areas on the lateral venter of thoracic segments in some Eunicida, where they replace ventral cirri; cf. lateral shields.ventral shield:
glandular, segmentally arranged pads on the mid-ventral thorax in many Terebellida.vermiform:
worm-like in form.vestimentum:
body region in vestimentiferans (Siboglinidae), on which lateral flaps enfold the anterior part of the body behind the plume.villus, villi:
series of small, digitate tubules arising from the contractile vessel of some sipunculans.vitellogenesis:
formation of egg yolk.winged capillary chaeta:
see limbate or bilimbate chaetae.Z
zygote:
product of fused haploid spermatozoa and ovum, forming a diploid cell.