important fisheries of the Atlantic coast of the United States by landed 

 value and weight. Hard clam in 1956 was 7th by value and 19th by weight of 

 meats. Being filter feeders, molluscan shellfishes are able to concentrate 

 particles, including radioactive particles, from large volumes of water. 

 These accumulate in filtering mechanisms, on body surfaces, and within the 

 digestive tract, so that high radioactivity may be present, even though the 

 radionuclides responsible are poorly absorbed and not concentrated within 

 tissues. The entire soft tissues of oysters and clams are utilized, whereas 

 only certain parts of most other seafoods are eaten. Thus, shellfishes may 

 be most hazardous to humans in contaminated areas. - J.L.M. 



345 



Chipman, Walter A., and P. S. Galtsoff. 1949. 



Effects of oil mixed with carbonized sand on aquatic animals. U.S. Fish 

 Wildl. Spec. Sci. Rep. — Fish. 1, 66 p., including illustr. 



There was no significant difference between clams in controls and in water 

 contaminated with various types of oil. Venus mercenaria was the clam used. 

 - J.L.M. 



346 



Chipman, Walter A., Theodore R. Rice, and Thomas J. Price. 1958. 



Uptake and accumulation of radioactive zinc by marine plankton, fish, and 

 shellfish. Fish. Bull. 58(135): 279-292. 



Venus (Mercenaria) mercenaria and other bivalve mollusks concentrate large 

 amounts of trace metals like Zn. Radioactive Zn added to the water was 

 taken up rapidly in great amounts. Considerable accumulation of nuclide 

 took place in gills and hepatopancreas . Nitzschia closterium took up large 

 amounts of Zn65 and transferred it to marine animals. Less Zn was found in 

 hard clam than in oyster, but more than in bay scallop. - J.L.M. 



347 



Christensen, Aage Moller. 1957. 



The feeding behavior of the seastar Evasterias troschelii Stimson. Limnol. 

 Oceanogr. 2(3): 180-197. 



Experiments were done with Protothaca staminea. (Abstracter's note: 

 P. staminea is sufficiently similar to Mercenaria mercenaria so that the 

 results probably are applicable also.) Seastars were able to open a clam 

 against known resistances in excess of 5,000 grams. If prevented from 

 applying force seastars still will succeed in feeding on clams, but 

 digestion is prolonged because it is difficult to insert all lobes of the 

 stomach into the prey. - J.L.M. 



348 



Christensen, Darryl J., C. Austin Farley, and Frederick G. Kern. 19 74. 



Epizootic neoplasms in the clam Macoma balthica (L.) from Chesapeake Bay. 

 J. Natl. Cancer Inst. 52(6): 1739-1749. 



Mercenaria mercenaria is mentioned in discussion, by reference to a paper 

 by Yevich (misspelled Yevitch) and Berry (sic), 1969, abstracted elsewhere 

 in this bibliography. These authors are said to have described a tumor of 

 germ cell origin in hard clam, which was thought comparable to granulosa 

 cell carcinoma in man. Christensen et al. comment that this sort of 

 comparison is questionable, because granulosa cell tumors have been dis- 

 tinguished from germ cell neoplasms on the basis of mesenchymal origin, 

 and presence of highly specialized endocrine tissues such as granulosa 

 cells has not been established in mollusks. - J.L.M. 



349 



Ciuchta, Henry P., and David E. Mann, Jr. 1961. 



Effects of dZ-., I- j and d-ephedrine on levarterenol tachyphylaxis in the 

 isolated heart of Venus mercenaria. J. Pharm. Sci. 50(8): 648-651. 



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