Colonies comprising many pedicellate hydrothecae arising from hydrorhiza overrunning stems and hydrorhizae of other hydroids.
Stolons tubular, sometimes contorted, perisarc thick. Pedicels simple, unbranched, variable in length, long, tubular, of same diameter as stolon; most pedicels with 3 or 4 obscure proximal annulations, pedicels thereafter smooth, sometimes with a few groups of undulations or joints marking site of regeneration. Pedicel ending in a slightly expanded distal shoulder, a flattened spherule between stem and basal chamber of hydrotheca.
Hydrotheca deeply campanulate, walls expanding smoothly from base to margin, basal chamber narrow, enclosed by outer walls, diaphragm marked by an annular thickening of wall; margin circular, crenulate, with 8–10 apically flattened cusps, embayments between U-shaped, an almost exact reverse image of cusps. Hydrothecal margins often with 2 or 3 widely separated regenerations.
Hydranth with c. 16–18 tentacles.
Perisarc of stems fairly thick, thinning distally along hydrothecal body to margin.
Colour: Colonies transparent and colourless to white.