370 
THE OCEAN WORLD. 
the larger side of their shell being uppermost. They assemble on 
sandy bottoms in considerable numbers. The byssus has in all ag eS 
fixed tlie attention of the Mediterranean fisher* 
men upon these curious shells. With its tuft of 
fine silky hairs, six or seven inches hi length, and 
its fine reddish-brown colour, 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 which there is nothing analogous in the world- 
The Maltese and Neapolitans still fashion soft 
tissues from it, but the stuffs so manufactured are 
pure objects of curiosity. 
Twelve species are described as living in the 
several seas. Pina nobilis (Fig. 155), the byssn^ 
of which was employed in the ancient Neapolitan 
industry, inhabits the shores of the Mediterranean- 
Pina bullata, Swainson (Fig. 154), is also a well-known species. 
The pond mussels, Anoclonta, are fonn 1 
in lakes, rivers, and seas of almost every 
region of the globe. Their shells ar e 
rounded or oval, generally very thin, xe ' 
gular, and equivalve, not gaping, the hing eS 
without teeth, whence their name from th e 
Greek, oSwros', without teeth. These shelj* 
theft 
Fig. 154. Pina bullata 
(Swainsonj. 
d 
,f 
are nacred inside, but very plain ; 
external epidermis being of a grave tint o 
greenish black. 
The Anodonta cygnea (Fig. III., Pi- d-' 
is broad, deep, and light, and is someth 0 ^ 
employed for skimming the cream 
off milk- 
The genus is divided into many group s ’ 
the principal forms of which are represent 
in Pl. XVI. 
Fig. 155. Pina nobilis, with its 
byssus (Linnteus). 
The river mussels, Unto, are, 
like the 
ot 
all countries. 
Anodontas, found in the muddy bottoms 
The animal resembles the Anodonta, but the shell p re 
