Dactylozooids

modified individuals in colonies of certain hydroid polyps.

Dactylozooids look like branched or unbranched tentacles with no mouth. The dactylozooids fulfill the function either of protecting the colony from its enemies (in Hydractinia) with the aid of numerous cnidoblasts, of capturing food (in Millepora and other hydrocorals), which they transfer to other individuals called gastrozooids for digestion (often a group of dactylozooids surrounds each of the gastrozooids that they serve), or of receiving stimuli transmitted to the entire colony.