Two rather old, yet interesting, animals.

We are just returned from an archaeological tour of Tunisia. Once I get my photographs sorted out I will post some highlights from a journey that was to take us from the ancient city of Carthage in the North to the Southern Roman frontier on the fringes of the Sahara.

For today, let me just show you a couple of interesting zoological items from the time of Caesar, from the Roman town of Colonia Julia Neapolis. Both are from the spoil heaps created during the excavation of the Roman town.

The shell on the left is a marine snail called Murex brandaris. This snail, like many other species in the family Muricidae, produces a secretion which is milky and colourless when fresh but which turns into a powerful and lasting dye when exposed to the air. This was the mollusc used by the ancients to produce the purple fabric dye known as Tyrian purple, or royal purple, or imperial purple. It was, of course, much prized by the Romans, who used it to colour ceremonial robes.

The odd looking thing on the right is a crushing tooth from a skate, or a ray, which I picked out from the excavated waste spoil from a Roman Garum works. Garum was a fish sauce, presumably similar to modern Thai fish sauce, greatly appreciated in Roman times as a seasoning. It was made by fermenting masses of rotting fish in the heat of the sun, for weeks on end, in vast sunken vats.