Scylla

sil′a, n. a six-headed monster who sat over a dangerous rock on the Italian side of the Straits of Me ina, over against the whirlpool of Charyb′dis on the Sicilian side.— n. Scyllæa (sil-ē′a), a genus of nudibranchiate gasteropods.— n.pl. Scyllar′idæ (-dē), a family of long-tailed, ten-footed marine crustaceans.