Family Sphaerocorynidae Prévot, 1959

Diagnosis: Colonies stolonal or erect; hydrocauli unbranched or sparingly branched, with terminal hydranths; perisarc thin, reaching hydranth; hydranth pyriform, with bulbous base and proboscis-like hypostome; no oral tentacles, but single, or partially fused capitate tentacles in whorls around broadest part of body; gonophores arising above or among tentacles as free medusae or fixed eumedusoids. Eumedusoid or free medusa with thick bell-shaped or conical umbrella; with or without apical projection, when present conical or dome-shaped, with broad apical chamber; manubrium flask-shaped, quadrate, or cruciform, mouth simple, round or cruciform; four tentacles, when present, with adaxial, evenly distributed, or spirally arranged nematocyst clusters, with a terminal, ellipsoid or spherical capitation; with or without abaxial ocelli; gonads adradial, confluent in perradii in mature specimens.