spicule
From ZooTerms (Dictionary of Invertebrate Zoology)
spicule (noun; Latin spicula, small spike): 1. Any minute pointed spine or process.
2. (Mollusca: Polyplacorphora) The dorsal girdle decorations of various size, shape and frequency.
3. (NEMATA) Blade-like, sclerotized male copulatory organs, usually paired, located immediately dorsad to the cloaca.
4. (Porifera) An element of the sponge skeleton, composed mainly of silica or calcium carbonate, and rarely spongin.
