40 THE OYSTER AND THE OYSTER INDUSTRY. 



BORING SPONGE. 



Boring sponge {Cliona celata) is the term applied to a yellow 

 sponge which begins its existence by boring (PI. XXI, lower left 

 figure) in the shell of the oyster, where it forms small tunnels, in 

 which it lives. The shell is gradually honeycombed, and the oyster 

 becomes weak and thin from the effort to seal up the openings where 

 the tunnels penetrate the shell completely. The sponge also spreads 

 over the outside of the shell and often smothers the oyster by its 

 ver}' size. No means of protection against the sponge can be sug- 

 gested, but fortunately it does not occur in sufficient numbers in 

 most regions to prove a serious menace. 



BORING CLAM. 



The boring clam (Martesia cuneiformis , M. smitJiii, and M. cor- 

 ticaria) is a species of clam which enters the shell of the oyster 

 by boring a small round hole and excavating in the substance of 

 the shell, at the inner end of the hole, a hemispherical cavity 

 (PL X, fig. 2) in which it then spends its life, often attaining a length 

 of three-eighths of an inch. The clam usually does not penetrate 

 the shell entirely and does not feed upon the oyster. It attains its 

 food through the external opening. It does comparatively little 

 damage to the oyster. 



WAFER OR "leech." 



This is a turbellarian worm (PL VI, fig. 2) of undetermined species 

 which on several occasions has destroyed large numbers of oysters in 

 the vicinity of Cedar Keys, Port Inglis, and Tampa, Fla. This worm 

 is nearly flat, more or less circular in outline, and is about three- 

 fourths of an inch long. It finds its way between the valves of the 

 oyster and feeds upon the meat, eventually killing the oyster. It 

 flourishes in water of fairly high salinity, and its ravages are checked 

 by lowered temperatures. No method of combating it can be 

 suggested other than a careful working of the beds and the use of 

 new air-dried cultch and fresh seed stock. 



TAKING OYSTERS FROM THE BEDS. 



Oysters are commonly taken by the use of hand tongs, patent 

 tongs, dredges lifted byliand or hand windlasses, or dredges raised 

 by engines or bolsters turned by the engine of the boat. These forms 

 of apparatus and the boats on which they are used are described 

 below. 



TONGS. 



Ordinary hand oyster tongs are shown in Plate XI, figures 1 and 2. 

 There are two long, fiat, smooth, wooden handles about 3 inches wide 

 and nearly 1 inch thick, bolted, riveted, or pinned together with a 

 wooden pin, scissors fashion, about 4| feet from one end (see figures), 

 leaving the long ends for handles. To the short end of each shaft is 

 secured at right angles a light iron bar, about 3^^ feet long, bearing 

 teeth, while above this bar are five or six still lighter bars or heav}^ 

 wires parallel to the bar and attached to the shaft. The ends of the 

 bars or wires are fastened together by short wires. The arrange- 



