phagosomes formed during phagocytosis and effect the degradation of enclosed 

 nonself materials. B-glucuronidase, acid phosphatase, alkaline phosphatase, 

 lipase, and lysozyme are associated with the cellular and the serum compon- 

 ents of the hemolymph of M. mercenaria. Lysozyme is released from cells 

 into serum during phagocytosis of Bacillus megaterium by M. mercenaria cells. 

 There are elevations in lipase and lysozyme levels in cells and serum of M. 

 mercenaria challenged with B. megaterium. This is interpreted to mean that 

 upon suitable challenge there is hypersynthesis of at least certain lysosomal 

 enzymes, for example, lipase and lysozyme, within actively phagocytosing cells, 

 and these enzymes are released in to serum where, at least theoretically, 

 they can act on susceptible nonself materials. Preliminary experiments indi- 

 cate that the released enzymes in serum do enhance inhibition and lysis of 

 certain microorganisms. Thus, the serum lysosomal enzymes may be considered 

 as induced humoral factors, although they are non-specific. - J.L.M. 



2097 



Chipman, W. A. 19 58. 



Accumulation of radioactive materials by fishery organisms. Gulf Caribb. 

 Fish. Inst., Univ. Miami, Proc. 11: 97-110. 



Detailed reference to Mercenaria mercenaria unlikely. Search terminated. 



2098 



Chipman, W. A. 19 60. 



Biological aspects of disposal of radioactive wastes in marine environments. 

 IAEA, Vienna. 



Unable to locate. Search terminated. - J.L.M. 



2099 



Clark, G. R. , II. 1977. 



Seasonal growth variations in bivalve shells and some applications in 

 archeology. N. Am. Paleontol. Conv. II, J. Paleontol. 51, Pt. Ill of III, 

 Suppl. to No. 2: 7 (abstract 25) . 



Shells of Mercenaria mercenaria collected alive at St. Catherine's Island, 

 Georgia, were examined in thin section and found to exhibit several kinds 

 of seasonal growth variation. Shell characteristics affected included sur- 

 face relief (ledging) , surface texture, disturbance lines, spacing of fine 

 growth lines, transparency and patterns of transparency, crystal size, crys- 

 tal orientation and extinction patterns, and offsetting of boundaries be- 

 tween shell layers. Some of these variations were found in all specimens, 

 while others appeared at random or seemed restricted to particular growth 

 stages. By making collections at different times of year, it was possible 

 to determine the season at which the changes took place, even though the en- 

 vironmental stimuli are not yet established. Shells of M. mercenaria were 

 also collected from human occupation sites (shell middens) and associated (?) 

 burial mounds. Comparison of growth variations noted in thin sections of 

 these shells with seasonal variations noted in recent shells has established, 

 in most cases, the probable season of occupation of the sites. - modified 

 author's abstract - J.L.M. 



2100 



Clarke, John R. 1978. 



The effect of high pressure on the rhythmicity of bivalve hearts. Comp. 

 Biochem. Physiol. 60A(2): 151-160. 



Mercenaria mercenaria hearts, quiescent in diastole, responded to 34 atmos- 

 pheric pressure changes with transient chronotropic excitations lasting for 

 35 to 80 seconds. In a hard clam heart which did beat spontaneously, beat 

 amplitude was reduced 50% by 34 atmospheres, and 80% by 68 atmospheres. At 

 136 atmospheres a reversible quiescence was induced. Preliminary studies on 

 M. mercenaria suggest a much greater inhibitory effect of pressure on this 

 species than on two subspecies of Modiolus demissus . - J.L.M. 



583 



