2 APRIL 1937, Page 9

MUSSOLINI AND THE MOLLUSCS

Ry PROFESSOR C. M. YONGE

The animal which forms the threads which the Italians are using is known to zoologists as pinna nobilis, and it has allies in all seas. All possess flat shells, pointed at one end and broad at the other, the resemblance to a half-opened fan being responsible for the common name, fan-mussel, which is given to the local species which is not uncommon off our southern shores. This animal has the distinction of being our largest mollusc, reaching a length of over a foot and a breadth of some eight inches. The fan-mussels of the Mediterranean are even larger, and are called jambon- neaux by the French owing to their likeness, in shape and colour, to a dried ham. A smaller species which is common in the West Indies is there known as the Spanish oyster.

All of these animals have the same habits. They live embedded vertically in mud or sand with the pointed end downwards and the broad end projecting for some little distance above the bottom. But any attempt to pull them out encounters great resistance, and it is only after much twisting and pulling that the animals are freed. The nature of the attachment is then apparent. It consists of a mass of fine fibres which protrude from between the two halves of the shell near the pointed end and is normally attached to stones beneath the surface.

These threads are known technically as the byssus, and they occur in many other bivalves. Our common mussel is fastened to rocks in the same manner, and so is the pearl oyster of tropical seas. One very beautiful orange-coloured bivalve actually uses these threads to construct a nest to which stones and debris are attached externally, and within which the animal lies concealed. The threads are formed in a special gland, from which a viscid stream emerges which is directed first in one direction and then in another. Where the fluid meets a hard surface it spreads out, forming a flat disc which, together with the thread behind it, quickly sets firm in water. In this way a secure attachment is eventually made. Broken threads are replaced by new ones, or the animal may voluntarily discard the threads. This happens in the case of young mussels, which can clitnb up the sides of aquaria by attaching themselves by byssus threads, pulling themselves up on these, then forming others higher up, releasing the first set, and so gradually progressing higher and higher.

The fan-mussel is notable for the length, delicacy and abundance of these threads. Those of the Mediterranean species early drew the attention of fishermen. The Greeks and Romans were both impressed with the quality of these reddish-brown threads which are as fine as silk and very tough, and have the advantage, when fresh, of being flexible. They wove them into a fabric and Emperors did not disdain garments manufactured from this unique cloth.

The collection and weaving of these threads has never entirely died out. It has been carried on by Neapolitans. Sicilians, Maltese and above all by the inhabitants of Taranto in easy reach of great beds of these animals in the Bay of Taranto. The crude threads, known as lana penna, were washed in soap and water and then dried and rubbed between the bands. They were next passed through combs of bone and of iron, a pound of coarse fibre being reduced in this process to some fifth of its original weight but consisting of the finest threads. Finally these were mixed with silk and spun on a distaff From this material gloves, caps, stockings, vests, mittens and other small garments were knitted. The finished product has been described as being of a "beautiful brownish-yellow colour (resembling the burnished golden hue of the back of certain flies and beetles), but very liable to be moth-eaten, and requiring to be wrapped in fine linen."

Such articles, which were far from cheap, were never manufactured, even at Taranto, on more than a very limited scale. They were at all times objects of curiosity rather than of economic use. It is recorded that some beautiful specimens of this fabric were shown at the Paris Exhibition of 1855. The eminent Victorian naturalist, Gwyn Jeffries, states in his British Concholoo, published in 1863, that at "our last Inteniational Exhibition a Cornish muff made of this material might have been seen by those disposed to venture into an obscure gallery in search of the few objects on natural history for which any space was allotted."

The revival and expansion of this ancient industry of the Mediterranean is a most unexpected outcome of Mussolini's Abyssinian adventure. Time alone can tell how successful the venture will be. But the threads of the byssus are brittle, they apparently invite the attentions of the clothes- moth, while it appears most Imlikely that the supply of fan-mussels, ample though this may have been as the raw material for the manufacture of curios for tourists, will be sufficient to supply the needs of modern industry. It will be the molluscs, and not Mussolini, who will decide the issue.