3/2 THE OCEAN WORLD. 



in a vertical position, the larger side of their shell being uppermost. 

 They are found on sandy bottoms in considerable numbers. The 

 byssus has in all ages fixed the attention of the Mediterranean fisher- 

 men upon these curious shells. With its tuft of fine silky hairs, six or 

 seven inches in length, of a fine reddish-brown hue, articles of luxury 

 are formed, which are often mentioned by the Latin writers. The 

 threads of the byssus, which are remarkable for their unalterable 

 colour, were formed by both Greeks and Romans into a fabric to 



-urJc:'jI 



Fig. 167. Pinna nobilis, with its byssus (Linnseus). Fig. 168. Pinna hullata (Swainson). 



wofo'.) Ysfoni* jf^oifflferft ,ftldi bnn jjdi' .a^i'l) ru.ur! Jxhb c oj oaniiM 

 which there is nothing analogous in the world. The Maltese and 

 Neapolitans still fashion soft tissues from it, but the stuffs so 

 manufactured are mere objects of curiosity. 



Some thirty species are described as living in the several seas. 

 Pinna nobilis (Fig. 167), the byssus of which was employed in the 

 ancient Neapolitan industry, inhabits the shores of the Mediter- 

 ranean. Pinna bullata, Swainson (Fig. 168), is also a well-known 

 species. 



Our twenty-first family, Ostreidse, contains the genera Lima, 

 Spondylus, Pecton, Anomia, and the all-important genus Ostrea* 



