Cidaris

Cidaris, a genus of Sea-urchins (q.v.), and type of a family (Cidaridae) with very long spines. The most of the members of the family are fossil forms, but over a score of living species are known. Doroeidaris papillata is occasionally dredged to the north of Scotland, and its beautifully marked spines in some instances measure over six inches in length, being often twice as long as the cross diameter of the shell. It is sometimes popularly called the Piper from a fanciful resemblance to bagpipes.