when the conch buries in the bottom. In some cases a conch will work away 

 at a clam for several days without penetrating, and then may desert the clam. 

 In one series of observations 52% of the sites of attack were posterior over 

 the clam siphons, 27% over the midventral region, and 21% over the anterior 

 portion opposite the siphon. Selection of site may be influenced by flow 

 from the excurrent siphon. Sometimes the operculum of the conch also may be 

 wedged between the quahog valves. There was no evidence that the conch may 

 pour a secretion into the prey to kill it. Circumstantial evidence denied 

 the possibility, because attacked but unopened clams with holes in the shell 

 were active weeks later. In 23 days in an aquarium 69 mussels, 17 quahogs 

 0.8 to 2 inches long, 3 soft clams, and 1 razor clam were consumed. Mussels 

 were attacked more readily than quahogs. In one experiment a conch consumed 

 one quahog every 5 days. (Abstracter's note: oublication date probably later 

 than 1949.) - J.L.M. 



271 



Carriker, Melbourne R. 1950. 



Predation of clams and oysters by conchs. Atl. Fisherman, Feb. 1950: 18, 37. 



This article consists of extracts from an earlier paper, not identified, by 

 the author. Some original data are included, but most information was taken 

 from the literature. Conchs showed a decided tendency to prey upon thinner 

 shelled mollusks, like mussels, first. Quahogs offer the greatest resistance 

 to predation. The method of predation on quahogs is described from Colton 

 (1908) , abstracted elsewhere in this bibliography. A conch will work on a 

 hard clam for as long as 7 days in an aquarium without penetrating, then may 

 desert the clam. The predator only occasionally returns after deserting an 

 individual clam. Out of 37 quahogs - placed with one large conch in an 

 aquarium, 15 were opened and 10 were attacked but not opened. Only twice 

 did a conch return after the first attack failed. Selection of site of 

 attack may be influenced by flow from the excurrent siphon of the prey. 

 - J.L.M. 



272 



Carriker, Melbourne Romaine. 1950. 



Killing and preservation of bivalve larvae in fluids. Nautilus 64(1): 14-17. 



Retention of larvae in fluids rather than in slide preparations has many 

 advantages. Among preservative fluids tried were 1% formalin, 4% formalin, 

 and mercuric chloride. Best results were obtained with 1% formalin. Formula 

 for the preservative was: formalin 10 cc , commercial sugar 100 g, filtered 

 bay water (20 to 30°/°°) to make 1,000 cc , alkalized to approximately pH 10 

 with sodium bicarbonate. Solution pH should be held above 7. - J.L.M. 



273 



Carriker, Melbourne Romaine. 1951. 



Observations on the penetration of tightly closing bivalves by Busycon and 

 other predators. Ecology 32(1): 73-83. 



In an aquarium conchs creep one centimeter in 6 to 12 sec, attracted by 

 water pumped out by clams. Even deeply buried quahogs are attacked. 

 Although Venus-like bivalves resist predation more than other pelecypods, 

 they are readily penetrated and consumed. Busycon holds the clam in the 

 hollow of its foot so that the ventral edges of the valves lie directly 

 under the outer lip of the conch shell. By slowly and strongly contracting 

 the columellar muscle the conch brings the margin of its own shell into the 

 slight depression between the clam valves. Pressing against the edge of 

 the valve farthest from it the conch chips off a piece. Relaxing and 

 contracting, the conch makes an opening large enough to allow it to wedge 

 its shell margin between the two valves. Sometimes the conch is unable to 

 make an opening, merely smoothing off the edges of the clam shell. Hence 

 the conch eventually deserts the clam. Of 37 clams placed with one large 

 conch in one experiment 15 were opened and 10 were attacked but not opened. 

 The operculum of the conch also has been seen wedged between clam valves in 

 nature. Although it has been reported that conchs may pour a secretion 



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