Olindiidae

Olindiidae is a family of marine hydrozoans belonging to the order Anthoathecata. These hydroids are sessile cnidarians that typically form colonies. They are characterized by their horny perisarc, a protective outer layer that covers the hydrocaulus and hydrothecae. The polyps within an Olindiidae colony are often dimorphic, with some individuals specialized for feeding (gastrozooids) and others for reproduction (gonozooids). Reproductive polyps give rise to medusae, which are free-swimming and are responsible for sexual reproduction. The medusae of Olindiidae are typically small and bell-shaped. This family is found in various marine environments, primarily in temperate and tropical waters worldwide. Species within Olindiidae exhibit a range of growth forms, from encrusting to erect and branching colonies. Their diet generally consists of small planktonic organisms captured using nematocysts, the stinging cells characteristic of cnidarians. The life cycle involves both a sessile polyp stage and a free-swimming medusa stage.