1822 (Say, 1822) ; and something of its destructiveness to oysters is not indicated 

 until 1843 (DeKay, 1943) The writer suggests nonetheless, that drills have probably 

 been predators of epifaunal bivalves like oysters since the evolution ir Urosalpinx of 

 the present drilling mechanism, and are as, or more, serious predators today than 

 in early colonial times. The following four points support the latter hypothesis . 



First, Urosalpinx, because of its small size, slow rate of movement, and 

 inconspicuous method of predation is easily overlooked. This would explain why 

 this snail went unnoticed by white man for a time and why it was not considered a 

 serious oyster predator until recently . 



Secondly, it is probable that modern oyster culture has tended to produce 

 a hardier stock of drills.' Oyster management practices over the decades have 

 changed me aspect of oyster communities from the reef to the unistratal cultivated 

 type, and in the course of this alteration have promoted a high degree of mixing of 

 oysters and of their closely associated drill predators over wide areas Such 

 mingling should result in hybridization among interbreeding populations of Urosal - 

 pinx Preliminary information on biological races indicates that such populations 

 may cover extensive geographic areas, and that introduction and survival of new 

 drills from distant estuaries is indeed a good possibility. It is also likely that muta- 

 tions have occurred favoring further adaptation of the drill to the cultivated type of 

 oyster community 



Third, the reported abundance of oysters in early colonial times does not 

 necessarily indicate the existence then of less destructive drills . Stauber and 

 T. C. Nelson (pers . com) draw attention to a modern oyster reef in saline intet - 

 tidal waters of Cape May, Delaware Bay, New Jersey, untouched commercially, 

 which for many years has supported an unusually dense population of drills, yet 

 has remained consistently productive . Stauber points out that each year »ew sets 

 of oysters occur in sufficient abundance to protect older oysters and to permit 

 survival of a portion of the new generation and suggests that this biotic balance 

 may have held in early colonial days . The inference here is that man in harvesting 

 oysters automatically joins the depredatory forces of drills . He differs from drills, 

 whose maximum damage is directed to the early stages ofthe oyster, in harvesting 

 the older stages and in so mar aging his grounds that the setting of larval oysters on 

 older oysters is reduced to a minimum , This procedure obviously reduces the 

 buffering effect of young oysters, a dominant characteristic of productive oyster 

 reefs, and encourages predation of older oysters by drills. 



Fourth, the explanation given in the preceding paragraph explains the 

 existence of oyster reefs in saline waters in the midst of drills; in zones of brack- 

 ish water the more characteristic environment of most oyster reefs in the early 



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