Protrochus africanus

The "slit" shells as they are known, are a group of living fossils, which were believed to have died out with the dinosaurs - 70 million years ago until they were discovered again last century. They are deep sea dwellers and live on sponges. These are rare shells and expensive to buy. But if you are a collector then you are a collector!!
Sorry it had to be another shell but just one of those bad days.