OYSTER INVESTIGATIONS IN GEOEOIA 



65 



which, oil. account of its weight and shape, does not sink in the mud, 

 may become a nucleus of a new oyster lied. Oyster larvae attacli 

 to it and bciiin to grow; young oysters in turu give support to the 

 following generations, with the result that oysters pile one on top 

 of another, forming heavy clusters. Under the weight of it the first 

 ones gradually sink in the mud and perish. When the cluster is 

 broken by the oystermen or by the action of waves and the shells 

 are scattered, they form new nuclei for the development of the bed 

 which grows along the tidal flat and convert it gradually into a 

 continuous and densely popidated oyster community. Various 



Figure 4. — Oysters growing on the stump of a fallen tree. Blackbeard River, Ci.i. 



Low tide 



stages of the development of an oyster bed can be seen in photo- 

 graphs taken in Georgia waters. (Figs. 3, 4, 5, and 6.) 



One of the interesting peculiarities of oysters living on soft mud 

 is their tendency to grow vertically, (Fig. 7.) Single live oysters 

 thrown on the mud and left lying on their sides in about three or 

 four weeks are found standing up vertically, with the anterior 

 (hinge) end buried in the mud and the very sharp posterior edges 

 of the shell (bills) just above the mud. The turning of the oyster 

 is apparently due to the gradual sinking of the heavier and narrow 

 hinge end; the process is facilitated by slight vibrations of the sur- 

 rounding soft medium caused by vigorous closing of the valves. 

 Keeping itself above the mud and silt, the oyster begins to grow 

 in length and develops into a long, sharp -edged specimen, which 

 is known as " coon " oyster. 



Two main factors are responsible for the development of this form : 

 The softness of the bottom and the crowded conditions caused by 

 the lack of material suitable for the attachment of the larvae. The 



