I discovered recently the existence of these two “ Métiers d'art ” timepieces made by Vacheron Constantin in 1953 . Both feature a cloisonné enamel dial made by Stern Frères and depicting a mermaid , probably the twin-tailed Melusina . Ref. 4710 in yellow...
Surprisingly, the black Melusina was sold three times at auction: I would not let go such a piece, personally, and I know Roni Madhvani deeply regret not have bought it (he could have before it came to market)... Best, Emmanuel