1505 



Price, T. J., G. W. Thayer, and G. B. Montgomery. 1974. 



Analysis of the invertebrates and sediments along shore-to-shore transects in 

 the Newport River estuary. Atl. Estuar. Fish. Ctr. , NMFS, Ann. Rept. to AEC : 

 183-198. 



Mercenaria mercenaria was not taken in all transects. In density it ranged 

 from 0.1 to 2.1 animals/m 2 where found. Ash-free dry weight ranged from 0.5 

 to 3.4 g/m2. - J.L.M. 



1506 



Price, T. J., G. W. Thayer, M. W. LaCroix,and G. P. Montgomery. 1976. 



The organic content of shells and soft tissues of selected estuarine gastropods 

 and pelecypods. Proc. Natl. Shellf. Assn. 65: 26-31. 



Mercenaria mercenaria from Cape Lookout, N.C. had 1.90%io.l8 ash-free dry 

 weight for shell, 79.79%±4.32 for meats, and 26.81%±10.47 for pallial fluid. 

 Total organic material in % was 38.60±3.83 for shell, 54.29*5.27 for meats, 

 and 7.41*2.99 for pallial fluid. - J.L.M. 



1507 



Pringle, Benjamin H. , Dale E. Hissong, Edward L. Katz, and Stefan T. Mulawka. 

 1968. 



Trace metal accumulation by estuarine mollusks. J. Sanit. Eng. Div., Proc. 

 Am. Soc. Civil Eng. Proced. Pap. 5870 (SA 3): 455-475. 



Average trace metal levels in M. mercenaria from about 100 stations from Me. 

 to N.C. in the natural environment were: Zn 20.6 ppm wet weight, Cu 2.6, Mn 

 5.8, Fe 30, Pb 0.52, Co 0.20, Ni 0.24, Cr 0.31, and Cd 0.19. In a simulated 

 natural environmental system quahaugs accumulated Cu from an environmental 

 level of 0.5 ppm at a rate of 0.06 g/kg/day and Pb from an environmental 

 level of 0.2 ppm at 0.63 g/kg/day at water temperatures of 10° and 20°C 

 respectively. Hard clams from Boston Harbor, at experimental temperatures 

 ranging from 4 to 12°C, and over a depletion time of 84 days lost Cu at a 

 rate of 0.05 g/kg/day, Mn at 0.095 g/kg/day, Zn at 0.12 g/kg/day, and Fe no 

 depletion. Along the Atlantic coast in the natural environment Zn levels 

 varied from about 10 to 40 ppm in hard clams, Cu from about 1-16 ppm, Mn 

 from about 1-30, Fe from 9-83, Pb from 0.1-7.5, Cr from about 0.2-5.8, Ni 

 0.1-2.4, Co 0.1-0.2, and Cd about 0.1-0.7. Levels of Zn, Cu, and Cd were 

 moderately to considerably higher in American oyster. It was concluded 

 that: species differ in uptake and concentration of a given metal; uptake 

 rates and concentration levels attained depend on the environmental con- 

 centration level; temperature, salinity, dissolved oxygen, and physiological 

 condition all affect uptake rate and concentration; for Cd, Cu, Pb,and Zn 

 the apparent toxicity determines uptake and concentration and the duration 

 of the experiment. Hard clams deplete themselves of heavy metals at lower 

 rates than soft clam. For any given metal and set of experimental conditions 

 hard clams had the lowest uptake rates and concentrations among soft clam, 

 American oyster, and hard clam. - J.L.M. 



1508 



Prosser, C. Ladd. 1940. 



Acetylcholine and nervous inhibition in the heart of Venus mercenaria. Biol 

 Bull. 78(1) : 92-102. 



Venus mercenaria heart is extremely sensitive to acetylcholine (ACh) . 

 Atropine does not antagonize this inhibition. The preparation from Venus is 

 so stable that it has some advantage over the commonly used leech muscle as a 

 test material. Clam heart can be tested in situ, it can be mounted in a tube 

 of seawater which can be replaced by test fluid, or heart can be mounted in 

 a chamber through which test fluid is perfused. In situ the threshold is many 

 times higher than by other methods. Normally a heart mounted in the morning 

 retains high sensitivity through the day. Sensitivity is greatest if clams 



421 



