540 



Eldridge, Peter J., Wayne Waltz, Robert C. Gracy,and Hurshell H. Hunt. 1976. 



Growth and mortality rates of hatchery seed clams, Mercenaria mercenaria , in 

 protected trays in waters of South Carolina. Proc. Natl. Shellf. Assn. 

 66: 13-20. 



Commercial use of hard clam in S.C. has not been large because the size of 

 the resource was not well known and markets were not developed. Hatchery 

 seed from Coastal Zone Resources of N.C. were used. Planting was in metal- 

 framed trays (119x58x14 cm) . Trays were lined with 1/4 in (6 mm) galvanized 

 hardware cloth with fiberglass insect screens in the bottom, then filled 

 with sand or sand with shell to a depth of about 10 cm. To reduce predation 

 by crabs, trays were covered with galvanized hardware cloth and wired shut. 

 This reduced predation only partially. Trays were placed in intertidal zone 

 in widely separated areas. Clams were planted at 200, 400, and 600/tray. 

 Those that died were not replaced. Clams were counted and measured every 

 3 months. After 18 months 51.3% survived at Bull Bay, 45.1% at Clark Sound, 

 and 4 9.8% at Albergottie Creek. Mean growth at different population 

 densities at the same site did not vary appreciably, but clams at two of the 

 sites grev; nearly twice as rapidly as at Bull Bay. This may have been 

 caused by the longer exposure at low tides at this site. Average monthly 

 . growth was 0.8, 1 . 5, and 1.8 mm. Growth rates varied with season, but growth 

 continued throughout the year. Water temperatures never dropped below 10°C. 

 - J.L.M. 



541 



Elliott, G. F., Jean Hanson, and J. Lowy. 1957. 



Paramyosin elements in lamellibranch muscles. Nature 180(4597): 1291-1292. 



In experiments with Mercenaria mercenaria and 4 other mollusks it was found 

 that some tropomyosin can be left behind in the paramyosin ribbons when 

 muscle is extracted with neutral hypertonic KC1 solutions. It was concluded 

 that water-insoluble tropomyosin is located in the paramyosin ribbons of 

 lamellibranch smooth muscles. The ribbons are sub-units of the filaments in 

 the intact fiber. It remains to be determined if these filaments also 

 contain actomyosin and if tropomyosin is involved in the contractile 

 mechanism. A full account of the structure of these muscles was to be 

 published elsewhere. - J.L.M. 



542 



Eltringham, S. K. 1971. 



Life in Mud and Sand. English Universities Press, London, vi + 218 p. 



A general text. References to Mercenaria (Venus) mercenaria are few. The 

 force that pulls the shell downwards in digging is only 5 to 6 gm in Mer- 

 cenaria mercenaria, which has an axe-shaped foot, compared to 800 g in Ensis 

 arcuatus, which has a bulbous terminal anchor. Burrowing sequence in a 

 generalized bivalve, similar to Mercenaria, is illustrated. In some lamelli- 

 branchs , gametogenesis will begin at a particular environmental temperature 

 but will not proceed to the production of gametes if temperature is experi- 

 mentally prevented from rising further. Venus mercenaria under such condi- 

 tions appears to be able to hold the gametes in cold storage and to release 

 them when conditions are suitable. - J.L.M. 



543 



Engel, Robert H., and Marilynn J. Neat. 1970. 



Glycolytic and gluconeogenic enzymes in the quahog, Mercenaria mercenaria. 

 Comp. Biochem. Physiol. 37(3): 397-403. 



Catalytic rates of glycolytic and gluconeogenic enzymes in quahog foot, mantle, 

 and gill tissues were extremely low compared to rat liver. Mammalian tissues 

 exhibit preferences for particular metabolic pathways, usually reflected in 

 catalytic capacities of critical enzymes. Analogous preferences were not 

 found in tissues of M. mercenaria. Absence of glucose-6-phosphatase in normal 

 quahog tissue suggests that the clam cannot complete synthesis of glucose via 



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