(noun; plural cirri
; Latin cirrus
, curl): 1. Any slender, usually flexible structure
2. Has been used for hair on appendages of insects and male copulatory organs in various invertebrates.
3. (Annelida: Polychaeta) Small, tentacle-like protuberances on the parapodia, peristomium and pygidium.
4. (Arthropoda: Crustacea) In barnacles, a thoracic multiarticulate appendage, usually flattened laterally and curled anteriorly, with food gathering function.
5. (Echinodermata: Crinoidea) The aboral ring of unbranched jointed appendages, curved and tapered at the end that aid in fastening to rocks, coral or soft substrata.
6. (Mollusca: Bivalvia) A bundle of fused cilia that filters particles from the water entering the gill.
7. (NEMATA) Elaborate cephalic appendages such as those found in Chambersiella.
8. (Platyhelminthes) The penis or copulatory organ of trematodes and cestodes.