328 
THE OCEAN WORLD. 
protection, seeking skelter at the least alarm between the valves oi 
the parent shell. The pad disappears after the young oyster has 
finally attached itself to a permanent bed of its own. 
Before this period of its life arrives, however, many are the dangers 
to which it is exposed : its enemies are numerous ; they he in ambush 
for it in every cranny ! It has to guard itself against eddies and 
currents which would drive it out to sea, and mud banks in which h 
would be smothered. Crustaceans, worms, and polypes, with other 
equally voracious marine inhabitants, prey upon it. Last, but not least, 
come the terrible and multiplied engines of the eager fisherman 
and we readily comprehend why the oyster is provided with such 
accumulated masses of ova. 
If the young bivalve is fortunate enough to escape all the snares 
and dangers we have enumerated, it grows rapidly. It is quite micro' 
scopic at the period of its discharge from the parent shell ; at one month 
it is of the size of a 
large pea, at the 
end of six months 
it is about three' 
quarters of an inch, 
a year after 
birth an inch and 
a half to two inches, 
Fig. 129. Young Oysters famished with locomotive organs. a[1( q at th® 
end of three years it has become merchandise : that is to say, it lS 
in a state to be sent to the parks for preservation and feeding. dn 
Fig. 1 30 we see a group of oysters* of various ages, attached to » 
piece of wood : a being oysters of twelve to fifteen months, b five or 
six months, c three to four months, n one to two months, and e oyster® 
twenty days after birth. 
The species of oysters usually eateu are the common oyster ( Ost>' e(l 
edulis, Linn.) of our own coasts and the opposite shore, and lh® 
horsefoot oyster (0. hippopus, Linn.). On the Mediterranean coa 3 *' 
are the rose-coloured oyster (0. rosacea, Favanue), and the milby 
at 
* We give this illustration as representing the comparative size of the oysters 
different ages ; but it is necessary to state that the specimens were artificially attach 
to the block by means of glue for exhibition. Oysters always attach themselves i 
the back of the rounded shell near to the hinge, as stated at p. 324. 
