preliminary one and that their results may be modified in the future; however, 

 because of the significance of their studies, their results have been included in 

 this review, with the hope that more research of this nature will be stimulated. 



^hirjments of drills arrived in lyiiliqrd^ (Connecticut, in the fallof 1950 

 from Rhode Island (courtesy of H. N. Gibjbs), Lpng Island Sound (Milford Staff), 

 New Jersey (H, H. Haskin)! Virginia (J. P Andrews), North Carolina (A. F. 

 Chestnut), and South Carolina (G. R. Lunz) Drills from each region were dyed 

 a different color for purposes of identification and then were maintained under 

 identical conditions until January of the same year, when the laboratory experiments 

 were begun. The following aspects of drill hehavjor were studied: temperature 

 at which (1) drills were able to nghten theniselves from an inverted position, (2) 

 feeding began, and (3) oviposition commenced. Groups of 25 or 5Q drills were used 

 in each experiment and almost all experiments yfere repeated three times; the same 

 drills were usually utilized only once. After acclimatization for an hour at each 

 experimental temperati<rre ; a mixture of drills from all geographic regions was 

 placed in a large tray with sea water maintained at the experimental temperature . 

 A summary of the results is presented in Table 14. 



Turning over . Qrills were placed at random in straight lines in the exper- 

 imental tray. As soon as they turned oyer onto the foot they were removed. At a 

 temperature qf 0°C a few? ds^lls, principally from Rhode Island and Long Island 

 Sound (and one from Virginia), extended the foot slightly but &*$ not turn over . 

 At this temperature no drill was able to attach to the bottom even if placed right 

 side up At 3°C approximately 50% of each of the Rhode Island and Long Island 

 Sound drills Tightened themselves within 90 minutes, whereas only a few from the 

 other areas were able to turn over . The higher degree of activity of the North 

 Carolina drills between 6 and 15* C than drills from South Carolina and Virginia 

 seems to set them apart from the latter. There appears to be no distinction between 

 the New Jersey and South Carolina drills at 9 D C since at this temperature both ex- 

 hibited 50% Tightening in 90 minutes, while at temperatures of 12 and 15° C the 

 Virginia drills appear to be the slowest to respond. 



Feeding , A few drills attempted to feed in the Rhode Island, Long Island, 

 New Jersey, and Virginia groups at 6°C; but no feeding was attempted by the North 

 and South Carolina drills'. At 12° C a significant difference was observed between 

 the two northern groups and all the others, since approximately 50% of each of the 

 Rhode Island and Long Island groups of drills and'less than 30% of any other group 

 fed. No appreciable differences were observed among the four southern groups. 



Qvi position Unfortunately these experiments were conducted either not 

 long enough or at insufficiently high temperatures to' obtain 50% egg deposition in 



$4 



