With the advent of civilized man and his subsequent exploitation of coastal 

 shellfish resources, the distributional pattern of the oyster drill changed markedly 

 and swiftly Storer (1931) rightly points out that more changes in animal dis- 

 tribution have occurred within the past 150 years than in all previously recorded 

 human history. Because of the close association of the drill with the oyster, it 

 has become an ubiquitous uninvited passenger in the transplantation, cultivation, 

 and harvesting operations introduced by man in the modern culture of oysters . 

 Many of these methods inadvertently favor its wide dissemination and propagation 

 For example, unless carefully checked, the transplantation of mfested oysters of 

 any age from one region to another may introduce drills and their egg cases, and 

 quite unintentionally live drills accompanying shell dredged for cultch may be 

 shovelled overboard on other grounds . In this manner the extension of the range 

 of this gastropod, unknowingly transplanted from its original haunts on barnacle 

 and black mussel bottoms and natural oyster reefs, has kept steady pace with in- 

 creased human utilization of new grounds for the culture of oysters (Adams, 1947; 

 Bureau of Statistics New Jersey, 1902; Cole, 1942; Dall, 1921; Elsey, 1933; Engle, 

 1953; Federighi, 1931c; Galtsoff et al„, 1937; Gibbs, pers . com ; Goode, 1884; 

 Hanna, 1939; Ingersoll, 1881; Lindsay, pers, com.; Moore. 1898a T. C. Nelson, 

 1922; Newcombe and Menzel, 1945; Orcutt, pers com,; Orton and Winckworth, 

 1928; Orton, 1930; Rogers, 1951; Sherwood, 1931; Stauber, 1943; Storer, 1931; 

 Townsend, 1893; Walter, 1910). "Once established on oyster beds the drill soon 

 attains high concentrations and persists there with phenomenal tenacity and success 

 unless effectually controlled by man. The density of these drill populations probably 

 fluctuates in large measure with the available food supply, drill breeding cycles, the 

 abundance of enemies, and gradual or catastrophic changes in the physical and 

 chemical environment . 



Specific 



Considerable information has been accumulated on the current geographic 

 distribution of the oyster drill, and will be presented in detail with emphasis 

 where available on the probable highways of dispersal. Just how far along these 

 dispersion routes drills are. able to survive and reproduce, particularly when the 

 routes extend latitudinally, is still a matter of speculation JMucn needed informa- 

 tion on biological races of drills and the adaptability of these races to extremes 

 in hmiting environmental factors will certainly help in answering these important 

 questions. Andrews (pers, com.) suggests that the distribution of drills by man 

 is more important within local areas than over long coastal distances Time may 

 well support his conjecture, but one cannot fail to be impressed by the great 

 quantities of living oysters, undoubtedly infested with drills at some stage of 

 development which have been transporfetl long distances along the east coast 

 of North America, to the west coast of North America, and to Great Britain . Such 



