190 SHELLS AND MOLLUSCOUS ANIMALS. 



may remember, and the young may learn, the 

 history of his tribe ; and as it is handed round the 

 assembly, each one reads the hieroglyphics traced 

 there, significant to the savage as is the written 

 document to the civilized man. 



The shell-fish called the Pinna is less common 

 on our coasts than the mussel, and has a frailer 

 shell, the two valves of which gape open at one 

 end. It is of a fan shape, and larger than the 

 mussel-shell. Indeed, the Huge Pinna (Pinna 

 ing ens], a native of the British seas, has a shell 

 twelve inches long, almost triangular in shape, 

 and horn-coloured. The threads by which the 

 different Pinnae attach themselves to rocks in the 

 sea, are much larger than those spun by our com- 

 mon mussel, and in Italy are woven into a silken 

 fabric. They are of a fine glossy brown colour. 

 The ancient Romans greatly prized articles manu- 

 factured from this byssus, and at Naples and 

 Palermo, stockings, gloves, and a silky-like fabric 

 have, even of late years, been made from it. The 

 Italians have also fabricated a substance of it, in 

 some measure resembling our broadcloth, but it is 

 so expensive that a coat of this material costs 

 about ten pounds of English money. Stronger 

 still is the byssus of that shell of the Indian seas, 

 called the Great Clam, whose silvery inside often 

 shines among the shells of grottos. The cable 

 attached to this sometimes supports a shell of the 

 weight of four hundred pounds, and repeated 

 strokes of the axe are needed, ere the animal can 

 be dislodged from its hold. 



But of all the common shells which the tide 

 throws over the shore, none is more general than 

 that of the oyster (Ostrea edulis). There it lies. 



