8 THE FLATWORM AS AN ENEMY OF FLORIDA OYSTERS. 
may secrete itself or deposit its eggs should be removed from the 
vicinity of the bars. 
4. When it is desired to select a new area for planting and cul- 
tivation, it is advisable, other things bein Ba to choose those 
localities where the water has sufficient depth to prevent overheating 
in summer, and also where the salinity may not attain too great a 
_ degree, as off affluents. 
EXPLANATION OF THE FIGURES. 
[All figures are two-thirds natural size.] 
Fig. 1. Left valve, showing a thin deposit of shell substance along the ventral margin 
from hinge to tips, and covering nearly one-half of the inner surface of the shell. The 
deposit had curled and peeled somewhat before the photograph was taken. The shell 
isempty. (Taken from Cedar Keys, Fla., Feb. 10, 1917.) . 
Fig. 2. Both valves, showing the results of the struggle between the oyster and the 
worm. Notice the shell deposits, particularly along the ventral margins. Parts of the 
meat are still clinging to the shell at the muscle scar. The worm had escaped. 
(Taken from Cedar Keys, Fla., Black Point Bars, Feb. 12, 1917.) 
Fig. 3. Left valve with the meat, and the turbellarian in position near the adductor 
muscle. Notice the shriveled condition of the oyster, and the retreat of the mantle 
from the edges of the shell. The worm had contracted to about one-half of its spread- 
ing capacity. (Taken from Port Inglis, Fla., Feb. 10, 1917.) 
Fig. 4. Left valve with oyster showing the gills. Notice the ‘‘ridges” near the hinge 
and along the ventral margin. The oyster was shriveled and dead. The worm had 
escaped. (Taken from Port Inglis, Fla., Feb. 10, 1917.) 
Fig. 5. Left valve, showing that the space occupied by the oyster was reduced, be- 
fore death, about one-half. Notice the ‘‘ridge,’’ beginning at the dorsal margin, then 
crossing adjacent to the hinge to the opposite side and extending to the tips. (Taken 
from Cedar Keys, Fla., Feb. 10, 1917.) 
Fig. 6. Left valve, showing the reduced space occupied by the oyster just previous 
to death. Notice the two ‘‘ridges” or successive stages of retreat along the ventral 
margin, and the spreading out or fan-like condition at the tips. (Taken from Cedar 
Keys, Fla., Feb. 10, 1917.) 
Fig. 7. Both valves, showing shell deposits of conchiolin and calcium carbonate. 
(Taken from Cedar Keys, Fla., Black Point Bars, Feb. 12, 1917.) 
Fig. 8. Both valves, showing deposits of conchiolin and calcium carbonate. (Taken 
from Cedar Keys, Fla., Black Point Bars, Feb. 12, 1917.) 
