2) 8 MOLLUSCA. 
at the tables of the rich. In many places, they in a great 
measure support the children of our maritime population, 
and, in the Western and Northern Islands of Scotland, have, 
in years of scarcity, prevented the death of thousands. 
The kinds chiefly used in this country, as articles of sub- 
sistence, are bivalves, belonging to different genera. Among 
these the Oyster (Ostrea edulis) holds the most distin- 
guished place. This shell-fish is very widely distributed in 
nature, being found in the seas of Europe, Asia, and Africa. 
But, since the days of the luxurious Romans, the oysters of 
Britain have been held in the highest estimation. They 
are found on various parts of our coasts, from the southern 
shores of England, to the sheltered bays among the Zetland 
Islands. They prefer a rough or rocky bottom, in from 
five to twenty fathoms water. They are fished up with a 
dredge and an open boat; sometimes, when in shallow 
water, with a rake or tongs. They are either conveyed 
directly to the market, or are placed in artificial ponds of 
sea water, where they increase in size, and acquire a fine 
green colour. In England this process of fattening, as it is 
termed, is chiefly conducted at Colchester, but the oysters 
are obtained from the little creeks between Southampton 
and Chichester. This fishery on the coast of England is 
supposed to give employment to ten thousand people, so 
that, independent of the addition which it makes to the 
articles of subsistence, it must be regarded as a valuable 
nursery for seamen. As an article of food, oysters are 
light and easy of digestion, and may be eaten in great num- 
bers without inconvenience. They are used either raw or 
when pickled. In the last form, they are sent to different 
parts of the country, and even constitute an article of ex- 
port. In Scotland, the principal oyster fishings are in the 
