THE OYSTER AND THE OYSTER INDUSTRY. 21 



themselves will assume the same general physical and biological 

 characters in so far as their environments permit. 



The natural beds of the Atlantic and Gulf coast practically all lie 

 like islands in a sea of mud more or less soft. In some places the 

 oysters are in clusters rooted in the mud, in others the substratum is 

 hard to a greater or less depth, but examination will show that this 

 hardness is in most cases superficial, and below it lies mud of a con- 

 sistency corresponding to that which surrounds the bed. There are 

 a few beds which have grown on rocky bottom, and there is a larger 

 number lying on firm, unshifting sand; but there are few rocky out- 

 crops on the coast south of New England, and most sandy areas tend 

 to shift more or less and engulf such oysters and shells as may be 

 lying on them. The oyster is an inhabitant, par excellence, of the 

 muddy bays, sounds, and lagoons, and in them attains its best 

 development. 



In tracing the history of any oyster bed, reference must be made 

 to the nature and characteristics of the young oyster as it develops 

 from the egg. As has been explained on page 13 the embryo oyster 

 is a minute organism endowed with certain feeble powers of locomo- 

 tion, which are sufficient for awhile to keep it suspended in the water 

 and permit its being carried by the currents. In some cases it may 

 be carried several miles from its parents before the setting stage is 

 attained. The chances arc many that when this happens it will lodge 

 on mud and end its story, for so small is the larva at this stage that 

 a mere film of ooze suffices to stiffc it. If, however, by rare good 

 fortune it, at this time or just before, comes into contact with a shell, 

 pebble, twig, rocky ridge, or other clean body, whether at the bottom 

 or not, it speedily attaches itself and continues its growth. 



So abundant is the supply of larva^ in any prolific oyster region 

 that ordinarily several or many will attach to each square inch of 

 clean surface, and a shell may fiu-iiish attachment for a hundred or 

 more. Under such circumstances there soon begins a struggle for 

 existence that is none the less rigorous for being purely passive. As 

 the young ovsters grow there is not room for all, and tlie more vigor- 

 ous ones, themselves distorted by the crowding, overgrow, stifle, 

 starve, and eventually kill those of slower growth or less advanta- 

 geously situated. At the end of the first year there has developed a 

 cluster of perhaps from two to a dozen young oysters growing on the 

 original shell, all projecting upward and crowding one another into 

 long, narrow shapes. Upon the projecting mouths of these shells 

 there is another set of spat on the succec(hng year, and as this grows 

 some of the survivors of the earlier generation are in their turn 

 crowded and killed. The result of this is that in the course of a few 

 years there is formed a cluster like an inverted pyramid with its apex 

 being gradually driven into the mud by the increasing weight above, 

 while its broad base is made up of several generations of living oysters 

 attached to the dead shells wnich constitute the middle parts. The 

 oysters around the edge where they have room to grow arc often of 

 fair shape and quality, while those more centrally located arc irreg- 

 ular, h>ng, narrow, and usually poor, owing to their crowded condition 

 and difficulty in obtaining food. 



From the decay of the hinge ligaments of the dead valves, the cor- 

 roding effect of boring animals, and the solvent action of seawater on 

 the limy shells, these top-heavy clusters tend to break up under their 



