Mistakidis (1951), Orton (1930), Stauber (1943), and the writer (1954), illustrate 

 that as water temperatures descend in the fell oyster drills at least in the north- 

 ern areas of their geographic distribution exhibit the following general movements: 

 those inhabiting subtidal bottoms crawl off elevated objects onto the surface of 

 the bottom and a number oury in the sediment; some of those in intertidal areas 

 burrow in the bottom and others probably migrate into deeper water . The reverse 

 migration takes place as water temperatures mount in the late spring. 



Federighi (1931c) noticed in North Carolina that drills retained in running 

 sea water aquaria maintained at temperatures prevailing outdoors became inactive 

 below 10° C (see Table 13) remaining attached to the substratum or lying passively 

 on the bottom A temporary rise in temperature above 10 °C anytime during the 

 winter stimulated sJjght locorao'ory activity and the activity increased as the tempera - 

 tuf© ascended. Gatlsoff et al. (1937) working in the laboratory in the northeastern 

 states disclosed that in water temperatures ranging from -3.0 to 9.6°C locomotion 

 in drills slowed to a rate of 0.024 cm. /nun, as the temperature descended to 4.5°C, 

 and completely ceased below 2°C. At temperatures below 2 C C drills either 

 hibernated on the surface or buried in the bottom attached to partially buried 

 oysters shells, and other hard objects, with the tip of the siphon projecting 

 slightly above the surrounding bottom. Loosanoff and Davis (1950-51) m laboratory 

 experiments have found that a few drills in lots from Rhode Island, Long Island 

 Sound, and Virginia extend the foot slightly but do not turn over when on their backs 

 at a temperature of O'C. At 3°C drills from these regions and also from New Jersey 

 and North and South Carolina are able to turn over. None of these drills was able 

 to attach at 0°C (Table 14). Galtsoff et al. (1937) uncovered no evidence that drills 

 seek and congregate in cavities of empty shells for protection during cold weather . 

 Adams (1947) noticed that hibernating drills attached to oysters and shells became 

 coated with a layer of silt which hides their typical form and makes them very 

 difficult to detect. Engle (1935-36) and Stauber (1943) both observed in the field 

 in New Jersey that not all drills bury in the bottom since some were found deeply 

 wedged in crevices formed by clusters of oysters. Stauber reports that drills 

 migrating off intertidal reefs in the fall were discovered later more or less 

 completely buried in the bottom around the edges of the reef usually clinging to 

 shell and with siphons oriented upward and presumably in contact with the water. 

 Engle (1935-36) writes mat in the winter in Delaware Bay the drill dredge collected 

 drills on hard as well as on soft bottom, and that numerous drills were collected 

 with a drill dredge equipped with a scraper bar, indicating that the snails were 

 present on the surface or not far below it . 



In order to obtain further information on the wintering over behavior of the 

 oyster drill the writer (1954) carried out a series of parallel field and laboratory 

 studies in 1953-54. Oyster drills collected in Shark River, New Jersey, were 

 maintained in an aquarium in a closed running sea water system in which water 



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