About Thuridilla gracilis (Risbec, 1928)
This species, Thuridilla gracilis, can reach a maximum size of 25 mm. Its body is partially covered by the fold of its lateral parapodia. The mantle is black, crossed by 8 to 10 fine white longitudinal lines, which are sometimes dotted with blue spots. The edges of the parapodial lapel and the rhinophores are often orange. The smooth rhinophores may be whitish, with no lines on their surface. This species is found in the Tropical Indo-West-Pacific. It inhabits the external slope of coral reefs, the top of reefs, and lagoons, and typically occurs in shallow water.
