Guide to the Shallow Water (0-200 m) Octocorals of the South Atlantic Bight.
S. T. DeVictor
& S. L. Morton, 2007

Glossary of Octocoral Terms (adapted from Bayer et al. 1983)

Anthocodia (p. Anthocodiae) – distal part of a polyp including the mouth, neck and tentacles, which may or may not be retractable into coenenchyme.
Anthostele – the lower part of the polyp consisting of the gastrodermal canal where it penetrates the coenenchyme; typically not visible on the surface of the colony.
Arborescent – tree-like branching pattern, generally comprising a bare stalk and polyps arranged on the distal branches and twigs (e.g. Pseudodrifa nigra).
Armature – the arrangement of the sclerites on the head of a polyp.
Autozooid – a polyp containing eight tentacles and mesenteries; in dimorphic colonies, they are larger than siphonozooids.
Axis – inner supporting structure of some octocoral colonies; may or may not contain sclerites; may be horny and/or calcareous, hollow or solid.
Boundary canals – in Scleraxonia, canals that run longitudinally throughout colony, separating medulla from cortex.
Calyx (p. Calyces, adj. Calicular) – stiff, projecting portion of the coenenchyme, typically reinforced by modified sclerites, into which the anthocodia may retract.
Capitate – unbranched colonies with a disk-like, spherical or hemispherical terminus on a narrow stalk, commonly resembling a club or torch (e.g. Nidalia occidentalis).
Capstan – an elongate sclerite with two girdles of warts or tubercles at each end (e.g. Leptogorgia hebes); often named by number of tubercles (e.g. triradiate capstan).
Coenenchyme (adj. Coenenchymal) – the common colony tissue between the polyps, consisting of mesoglea penetrated by solenia and gastrodermal canals and containing sclerites.
Collaret – a ring of transversely-arranged, bowed anthocodial sclerites located below the bases of the tentacles; typically associated with points (see below), forming a ‘collaret and points’ arrangement.
Contractile – ability of an anthocodia to reduce in size without inversion into the upper part of the anthostele within the coenenchyme, often accomplished by folding the tentacles inward.
Cortex (adj. Cortical) – In Scleraxonia, the layer of coenenchyme surrounding the medulla.
Dichotomous – branching pattern displaying a repeating bifurcation (e.g. Iciligorgia schrammi).
Digitiform – unbranched, finger-like colony form (e.g. Bellonella rubistella)
Dimorphic – having two types of polyps, autozooids and siphonozooids (e.g. Pennatulacea).
Disk-spindle – spindle-shaped sclerite that displays the fusion of warts into girdles on one or both sides (e.g. Leptogorgia setacea).
Double cone – a spindle-like sclerite with a medial constriction and acute ends (e.g. Viminella barbadensis).
Double head – a sclerite with a medial constriction and blunt ends (e.g. Viminella barbadensis).
Fistulose – a state in which the end of a flattened branch is rolled inward, partially fusing and forming a terminal groove (e.g. Iciligorgia schrammi).
Foliated club – elongate sclerite with an enlarged end adorned with leaf-like or spinous processes (e.g. Pseudodrifa nigra).
Foliose – resembling a leaf; dorsoventrally compressed and broad (e.g. Renilla reniformis).
Lobed – colonies with a few short, stout branches, often with clusters of polyps at tips (e.g. Pseudodrifa nigra)
Loculation (n. loculus, n. p. loculi )– the presence of spaces between layers of gorgonin in a holaxonian axis, which may be filled with calcified material, often very prominent in Plexauridae (loculi refers the pockets or empty spaces between the layers).
Medulla – inner supporting structure of a scleraxonian colony, comprised of sclerites often bound together with various amounts of horny gorgonin.
Monomorphic – having one type of polyp, autozooids.
Monopodial – branching in which a primary polyp gives rise to lateral daughter or budded polyps (e.g. Telesto sp., Carijoa riisei).
Oozooid – enlarged and modified polyp of the pennatulacean colony bearing autozooids and siphonozooids.
Peduncle – often called a stalk, the lower, bare portion of a pennatulacean colony that anchors in soft substrate.
Pinnate – branching in one plane that appears feather-like (e.g. Muricea pendula).
Planar – branching colonies that grow in one plane; fan-like.
Plate – a broad, flat, irregularly shaped sclerite (e.g. Scleranthelia rugosa).
Platelet – a small flattened sclerite of diverse outline (e.g. Sclerobelemnon theseus).
Points – sets of anthocodial sclerites, often bent spindles, forming eight longitudinal groups at the base of each tentacle; located above the collaret (if present), forming a ‘collaret and points’ arrangement.

Polyp leaves
– flattened expansions bearing secondary polyps in some pennatulaceans, such as Virgulariidae.

Polyp mounds – raised regions of the coenenchyme into which polyps retract; not reinforced by modified or specialized sclerites.
Primary polyp – polyp (in Clavulariidae) giving rise to lateral or daughter polyps; often the polyp farthest from substrate.
Rachis – fleshy part of a tentacle from which pinnules arise; in Pennatulacea, the part of the oozooid that produces the other polyps.
Retractile – ability of an anthocodia to fully withdraw into the upper part of the anthostele within the coenenchyme.

Sclerite – microscopic, calcareous structures found in the coenenchyme, anthocodiae, and sometimes in the axes of octocorals.
Siphonozooid – in dimorphic colonies, a polyp with reduced tentacles and mesenteries; smaller and less conspicuous than autozooids.
Spindle – common sclerite shape displaying an elongate form and tapering ends (e.g. Gorgoniidae).
Stellate plate – flat sclerite with peripheral lobes, appearing star-like, sometimes with a protruding knob in the center (e.g. Bebryce parastellata).
Stolon – an extension of the coenenchyme that traverses the substrate and connects polyps or colonies, often broad and ribbon-like.