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THE AMERICAN NATURALIST [Vol. LIV 



England, have ventured to use it as food, but this is by no 

 means a common practise. The genus Urosalpinx is 

 closely allied to Murex- several of its species are found 

 on the east coast of the United States. Arnold (1916) 

 says of Urosalpinx cinerea: 



This well-known species is regarded by Chesapeake and Long Island 

 Sound oystermen much in the light of a plague. These active preda- 

 ceous mollusks live upon bivalves, and preferably upon oysters. They 

 bore a small hole through the shell of their helpless victims, and then 

 proceed to extract the succulent, fleshy animal from within. The oyster- 

 men call them by the suggestive name of "drill," and wage incessant 



Daugherty claims: "It is a feeder upon oysters;" and 

 Kellogg says in part : 



There are several species of the snails that are destructive to bivalves. 

 Among these the large winkles or conehs of northern shores do very 

 little damage; but some of the smaller forms, particularly the oyster 

 drill, cause large losses here and there along the Atlantic coast. . . . 

 The drill, or Urosalpinx, is most destructive to young oysters. It seems 

 to be unable to bore through the shell of large individuals. . . . Like 

 starfish, oyster drills were formerly not numerous on the New England 



Bay, and in the Chesapeake, they are abundant ... in Louisiana, a 

 larger drill, Purpura floridana, is sometimes very destructive. 



Opinions thus seem to vary as to the destructive habits of 

 some of the gasteropods upon bivalve mollusks, but the 

 findings of Dr. Copeland (1916) are very conclusive: 

 Busycon reacts positively toward oyster juice, in fact, the 

 oyster often forms a conspicuous part of its natural diet. 

 All the investigators, however, seem to agree about the 

 habits of Urosalpinx. In view of the fact that these gas- 

 teropods are esculent, injurious to other marketable mol- 

 lusks, near large cities, and generally easily obtained, it 

 seems rather strange that they are seldom found in the 

 market. Polynices lewisii, which is still quite abundant 

 in the upper part of Puget Sound, is generally destroyed 

 by the oystermen whenever found in the vicinity of oyster 

 fields. As a natural enemy, P. letvisii seems to ha\ e none 

 more dangerous than the twenty-rayed starfish ( Pycno- 



