During 1935 36, over a period of several summer months, Galtsoff et al. 

 (1937) carried out some migration studies in Delaware Bay, New Jersey, m which 

 they marked drills by dipping the spire into quick drying colored lacquer which 

 persists for several months. These drills were released in the center of large 

 areas on a variety of firm grounds devoid of oysters and shells and at depths varying 

 from 15 feet to low water mark . Wire cages baited with young oysters or filled with 

 shell were placed at successive intervals from the drills and examined daily. In 

 every case more marked drills migrated to the oyster baited cages than to those 

 filled with shell. Engle (1935-36) who has described some of these results in more 

 detail reports a maximum rate of 75 feet per day but shows that daily migratory 

 rates in excess of 18 to 24 feet per day were unusual. Twenty-nine to 67% of the 

 marked drills were recovered. These authors conclude that in search for food 

 U. cinerea is able to travel a considerable distance, and that high drill densities 

 may be correlated with the presence of an abundant food supply. It should be noted 

 that for the most part Federighi carried out his experiments on bottom covered 

 with oysters whereas Galtsoff et al„ used barren bottom and baited drill traps. 

 These authors stressed the maximum distances covered by the most active drills , 



In a total of 6 preliminary field experiments on the intertidal flats of 

 Delaware Bay, Haskm (1937) studied the movements of Urosalpinx in relation to the 

 factors controlling the direction of migration during the period June 15 to July 13, 

 1937. The bottom of these flats is composed of a loose mixture of sand and mud 

 and is irregular in contour, so that at low tide many bars are exposed while some 

 sloughs contain as much as a foot of water. During the studies water temperatures 

 taken daily usually at high water ranged from 18.0 to 33 .7"C . Salinities in the same 

 period varied from 18 5 to 23.6 o/oo. As a check on the direction of net current 

 flow, floats, weighted with small rocks so the weights remained on the bottom yet 

 required only a very slight current to move them along, were followed from one low 

 tide to the next. A total of 1, 309 drills marked with quick drying pigmented shellac 

 were released on bottom relatively free of food organisms, principally during low 

 water, and at stakes oriented with respect to reefs and bags of living oysters and 

 direction of current flow . Observation of the position of the drills was made mostly 

 on succeeding low water periods . In general percentage recovery of released drills 

 decreased with time, ranging from 76% in observations extending a little over one 

 day to 11% in an observation continuing for 7 days . Haskm found that U. cinerea 

 exhibited great variability in rate and direction of movement over the flats, and that 

 direction of current flow and the position of oysters were the primary factors in 

 determining the orientation of the drills . The apparent variability in drill responses 

 among the different groups resulted from variations in the relative strengths of 

 chemotactic and rheotactic stimuli in the areas of the different stakes . Some drills 

 averaged as much as 4 ,4 feet per hour for the period of 5 hours after liberation 

 (in one case a drill moved 6 feet in less than 1/2 hour after liberation), but a rapid 



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