50-67 mm. -» Irregularly ovoid, thin, flat, fragile shell with smooth regular margins. Brown to black with light brown to white irregular radial lines. Some specimens lack these lines altogether. The animal lives commensally with sponges. (67 mm) Distribution: Common on the beaches of Ras Sudr (northeast Gulf of Suez) after winter storms. I have never seen it outside the Gulf of Suez. The sponges are commonly referred to as Finger Sponges and are clearly different from those inhabited by Vulsella fornicata and V. vulsella.
Notes: The specimens without lines resemble Electroma alacorvi from the exterior, but one look at the hinge distinguishes them: C. picta has about ten strong regular ligament pits; E. alacorvi has none.