434 MARINE INVERTEBRATES 
as are the fenced-off acres of upland meadows. The business of 
the oyster-culturist is to plant the young oysters and watch their 
development, keeping the beds thinned, that the oysters may 
not be too crowded for their normal and symmetrical growth, 
and protecting them from their enemies, of which there are many. 
The principal enemies of the oyster’are the starfish and the pre- 
daceous mollusks Urosalpinx and Nassa. Whole beds have been 
known to be destroyed in a single night by the visitations of 
starfishes, hence a constant watchfulness is required on the part 
of the oysterman. Policing the oyster-farms is another of 
his cares, for pirates abound, and a bed may be robbed in the 
night as easily as an orchard may be despoiled of its fruit. Oys- 
ter-culture is carried on extensively in Long Island Sound, on the 
coasts of New Jersey and Virginia, and in the Chesapeake Bay. 
The oysters from certain localities are esteemed more than others, 
the flavor of the oyster being very dependent upon the purity 
of the water and on the organisms upon which it feeds. It has 
been definitely shown that oysters grown in contaminated waters 
have been the agents of transmitting disease, notably typhoid 
fever and cholera. 
Oyster-culture has reached the highest degree of perfection in 
France, where miles of muddy shores left by the ebb-tide are uti- 
lized for the purpose. The famous parc at Arcachon, covering 
ten thousand acres, illustrates the system generally practised. 
The spat is there collected on tiles coated with cement, piled in 
layers crosswise, and secured in crates. These tiles are exposed 
in favorable localities and collect the swimming embryos. The 
rough cement holding the spat is then chipped off the tiles and 
placed in wire trays. These ambulances, or caisses ostreophiles, 
placed between short posts, protect the fry from their ene- 
mies. At low tide the young oysters are carefully examined 
and sorted, and at the right age they are removed to open areas. 
The pare is divided into regular squares by canals of suitable 
width, some of the squares having banks and gates to retain the 
water of the receding tide if desired. Each man’s pare is sepa- 
rated from that of his neighbor by canals of greater width, and 
often by stakes having a few branches on the ends. These pi- 
