38 THE OYSTER AND THE OYSTER INDUSTRY. 



shells and other objects in the water (PL VIII, center). Masses of 

 these capsules are often found covermg oyster shells so thickly that 

 there is danger of smothering the oysters. From their reddish- 

 purple color these masses are often referred to as "red grass." 



The various species of drill possess a rasplike apparatus which 

 can be protruded from the mouth. With this they bore a hole 

 through the shell of the oyster (PI. VIII, bottom) and suck out the 

 contents. Drills destroy many young oysters, their thin shells 

 being relatively easily penetrated. After the oyster becomes older 

 its shell is heavy enough to resist the effort of the driU. 



In Long Island Sound it has been found that about the most 

 practical method of lessening the numbers of this enemy is the 

 following: The teeth are removed from an ordinary oyster dredge, 

 and a bag with meshes of an inch or less is put on in place of 

 the usual coarser one. After the oysters have been taken off 

 the bed for market or shifting, the specially equipped dredge is 

 used and everything left — shells, drills, debris, etc. — is dredged up 



Fig. 4. — Pogonias cromis, or drum fish. At times this fish destroys large numbers ol oysters. (After 



Jordan and Evermann.) 



and (lumped ashore to dry. Tlic drills die, and a good deal «f the 

 material may then be used as cultch. 



DBUMFISH. 



The fish known as the "black drum," Pogonias cromis (text fig. 4), 

 is found at intervals of time and place from New Jersey to Texas and 

 is often very destructive to oyster beds. It attains a length of 

 several feet and has a heavy body with large stout teeth. The 

 oysters are crushed, shell and all, by these strong teeth, the younger 

 thin-shelled ones bcin^, of course, especially subject to the depre- 

 dations of the drumfish. These fish go in schools and their attacks 

 are spasmodic, often whole oyster beds being cleaned out in a short 

 time and then, again, no drumfish being seen for several months 

 or years. 



Efforts have been made to kill or frighten away such fish by the 

 explosion of dynamite, but no particular success has been achieved. 

 In southern waters, especially in Louisiana, where oyster beds lie 

 in shallow water and there is not much tide, it has been found practi- 



