Clypeaster species
Species: Clypeaster	Order: Clypeasteroida
Locality: Madagascar, Tuléar region, trawled in 120 m by local fishermen	Dimensions: 64 x 62 mm
The seller labelled it Clypeaster eurychorius, but I have some doubt, if the taxon is correct. According to Heinke Schultz, Sea Urchins II, pages 539 and 540, C. eurychorius has open petals. In the specimen shown above they are definitely closed.