1908.1 NATURAL SCIENCES OF PHILADELPHIA. 3 



HOW FTJLGUR AND 8YC0TYPUS EAT OYSTERS, MUSSELS AND CLAMS. 

 BY HAROLD SELLERS COLTON. 



Since observations on the habits of Prosobranch moUusks are 

 fragmentary and few, I embraced an opportunity of studying Fulgur 

 carica, Fulgur perversa and Sycotypus canaliculatus under conditions 

 as nearly natural as one can hope to have in a laboratorj^ located 

 far from the sea. j\Iost of the observations were carried out in the 

 Vivarium of the University of Pennsylvania; these were supplemented 

 by studies on fresh material under more natural conditions at the 

 Fisheries Laboratory at Woods Hole.^ 



The individuals studied in Philadelphia had been in captivity a long 

 time. All had been there a year and many several 3^ears. The Fulgur 

 carica had come from Woods Hole and the Jersey coast. F. perversa 

 I had brought up from Clearwater, Florida, two years and a half 

 before. Of these latter none had died a natural death during that 

 time. 



The salt water aquarium in which they were confined was about five 

 feet wide and eleven feet long. There was three feet of water over the 

 greater part, but a shallow beach at one end. 



On the beach I was accustomed to place oysters that I kept as a 

 stock to feed the animals in this tank. Every week I chopped up an 

 oyster or two and distributed the juice and fragments all over the tank. 

 This stimulated the Fulgurs and Sycotypi to activity and to make 

 frequent raids on the Hving oysters on the beach. This led me to 

 inquire into the kind of food, the amount of food, and method of 

 feeding of these gasteropods. 



There is but one actual observation on the manner of feeding of these 

 mollusks that I have been able to discover. Stimpson (1860), in 

 speaking of Sycotypus, said: "In eating (it) applies end of proboscis 

 to the clam's foot, and with a sudden jerk of the lingual ribbon inward 

 and sidelong takes a strip of flesh." 



The "impression" that most persons hold with reference to the 

 manner of eating and the habits of the Sycotypus and Fulgur is expressed 

 by Herrick (1906) : " Since this animal is a great pest to the oystermen 

 and clam-diggers, .... it is of some interest .... to know .... 



' I am deeply indebted to the ITnited States Commissioner of Fisheries for the 

 use of a table at the Woods Hole Laboratory, to Dr. F. B. Sumner, the Director, 

 for many favors, and particularly Dr. E. G. Conklin for reading the manuscript 

 of this paper and for many helpful suggestions. 



