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 – the distal part of the polyp that contains the mouth, neck and tentacles and can be retracted into the calyx

Arborescent – tree-like branching pattern, generally having a bare stalk(s) and clusters of polyps at the terminal end (ex. Pseudodrifa nigra)

Autozooid – a fully developed polyp containing eight tentacles and mesenteries; in a dimorphic state, larger than siphonozooids

Axis – the inner supporting structure of an octocoral colony; may or may not contain sclerites; may be horny or calcareous, hollow or solid

Boundary canals – in the Scleraxonia, canals that run longitudinally throughout the colony and separate the medulla from the cortex

Calyx (Calyces) – the projecting portion of coenenchyme into which the polyps may be retracted

Capitate – see Clavate

Capstan – an elongate sclerite with two belts of warts or tubercles and terminal tufts at each end (ex. Leptogorgia hebes).

Clavate – resembling a club or torch; having an enlarged terminal end (ex. Nidalia occidentalis)

Coenenchyme – the visible tissue between polyps that contains the sclerites and mesoglea, and is penetrated by the solenia and gastrodermal canals

Contractile – state in which a polyp is only partially inverted into the calyx, or reduced in size

Cortex (cortical) – In the Scleraxonia, the layer of the coenenchyme that surrounds the medulla; the outer layer of a holaxonian axis surrounding the inner core; generally references the outer layer of a region

Dichotomous – a branching pattern displaying a repeating bifurcation (ex. Iciligorgia schrammi)

Disk-spindle – a spindle shaped sclerite that displays fusion of the belts of warts on one or both sides (ex. Leptogorgia setacea)

Digitate – colonies branching into a few finger-like lobes (ex. Titanideum frauenfeldii)

Dimorphic – having two types of polyps, autozooids and siphonozooids (ex. Pennatulacea)

Double cone – a spindle sclerite with a medial constriction forming two symmetrical, acute terminal ends (ex. Thesea nivea, Ellisella elongata).

Double head - a spindle sclerite with a medial constriction forming two symmetrical, blunt terminal ends (ex. Ellisella elongata).

Fistulose - a state in which a flattened branch is rolled inward at the terminal end, partially fusing and forming a terminal groove (ex. Iciligorgia schrammi)

Foliated club – and elongate sclerite with an enlarged end which is adorned with spines or tubercles (ex. Pseudodrifa nigra).

Foliose – resembling a leaf; dorsoventrally compressed and broad (ex. Renilla reniformis)

Loculation – the presence of spaces or layers filled with calcified material in the outer cortex of the holaxonian axis, often very prominent in the Plexauridae

Medulla – the inner supporting structure of a scleraxonian colony, comprised of sclerites

Monomorphic – having one type of polyp

Monopodial – branching in which a primary or terminal polyp gives rise to lateral daughter or budded polyps (ex. Telesto sp., Carijoa riisei)

Oozooid – the enlarged and modified polyp of the pennatulacean colony that bears the autozooids and siphonozooids; primary polyp

Peduncle – often called a stalk, the lower, bare portion of a pennatulacean colony that anchors in soft substrate

Pinnate – branching that appears feather-like, usually in one plane (ex. Leptogorgia hebes)

Plate – a flat, irregularly shaped sclerite (ex. Scleranthelia rugosa)

Platelet – a small, flattened rod that appears flat under coarse magnification (ex. Sclerobelemnon theseus)

Polyp leaves – the flattened expansions bearing secondary polyps in some Pennatulaceans, such as the Virgulariidae

Rachis – the fleshy part of a tentacle from which pinnules arise; in the Pennatulacea, the part of the oozooid containing the polyps

Retractile – state in which a polyp can be fully inverted into the coenenchyme

Sclerite – the microscopic, calcareous structures that are found in the coenenchyme and sometimes the axis of octocorals.

Siphonozoid – in dimorphic state, a polyp with reduced tentacles and mesenteries; generally smaller and less conspicuous than autozooids.

Spindle – a common sclerite shape displaying elongate form and tapering ends (ex. Gorgoniidae)

Stellate plate – a flat sclerite with strong lobes, appearing star-like, often with a protruding knob in the center (ex. Bebryce parastellata)

Stolon – an extension of the coenenchyme that traverses substrate and connects polyps or colonies, often in ribbon-like or sheet-like habits

Terminal polyp – the polyp (in Clavulariidae) gives rise to lateral or daughter polyps; often the polyp reaching the farthest extension from the substrate. In Pennatulaceans, the distal end of the rachis or primary polyp.