1717 



Stafford, J. 1912. 



On the recognition of bivalve larvae in plankton collections. Contr. Canad. 

 Biol. 1906-10(6) Rept. 14: 221-242. 



This wordy and somewhat rambling paper mentions in the introduction some 

 conflicts between quohog (sic) and oyster industries. The quohog fishery 

 opened in Sept, a month before opening of the oyster season, and stirred up 

 sediment which, according to the author, interfered with oyster setting. 

 At the close of the spring season an extension of time was allowed to dispose 

 of clams on hand. This led to nightly poaching of oysters as well as hard 

 clams. Venus mercenaria was distributed geographically in approximately the 

 same places as Ostrea virginica, from Bay Chaleur to the southern coast of 

 Nova Scotia, restricted to favorable areas. A considerable hard clam 

 industry had developed. Clams were stored for weeks in large wooden trays 

 anchored below low-tide mark, and were shipped in barrels or more frequently 

 in bushel or 1 1/2 bu sacks to New York and Chicago. Quohog larvae were 

 recognized by comparison with known larvae of other species, and by their 

 presence in areas populated by adult hard clams and absence in areas not 

 populated by adults. In 19 09 the first quohog larva appeared in plankton 

 collections near Bay du Vin. A week later quohog larvae were abundant. The 

 early stages remain in the straight-hinge form when other bivalves are 

 recognizable by their umbos. Umbos begin to show at a length of about 25 

 units on the stage micrometer (1 unit=6.9 mikra) . After the umbo is formed 

 it is easy to distinguish quohog larvae from those of other species. 

 Drawings of various stages are given in figures 25-30 of plate XXIII. - J.L.M. 



1718 



Stafford, Walter F. , III, and David A. Yphantis. 1972. 



Existence and inhibition of hydrolytic enzymes attacking paramyosin in 

 myofibrillar extracts of Mercenaria mercenaria. Biochem. Biophys. Res. 

 Commun. 49(3): 848-854. 



Paramyosin is attacked by at least 2 hydrolytic enzymes in extracts of 

 adductor muscle of M. mercenaria under usual isolation conditions. EDTA- 

 inhibited and phenylmethane sulphonyl fluoride-inhibited hydrolase activities 

 have been identified. When paramyosin is extracted into high salt at pH 

 7.5 in presence of 0.01 M EDTA, a new molecular species of paramyosin is 

 isolated, with molecular weight about 5,000 daltons higher than material 

 isolated by previous procedures . A high resolution acrylamide gel 

 electrophoresis technique, using split gels, detected small differences 

 in apparent sub-unit molecular weight. - modified authors' summary - J.L.M. 



1719 



Stanley, Steven M. 1970. 



Relation of shell form to life habits of the bivalvia (Mollusca) . Geol. Soc. 

 Am., Mem. 125, 296 p. 



Meraenaria mercenaria (Linne) 



The shell is very large (maximum length 12 to 13 cm) and elliptical in lateral 

 view, with a somewhat pointed posterior. It is strongly prosogyre, elongate 

 posteriorly, and moderately inflated. Valves are thick and slightly rugose. 

 Ornamentation consists of sharp, fine concentric ridges present only 

 anteriorly and reduced by abrasion in adults, but covering entire valves of 

 first-year spat. Interior ventral valve margins are denticulate. L/H 1.25, 

 H/W 1.52, AL/L 0.25, T.I. 0.60. L= length; H= height; W= width; AL= anterior 

 length T.I.= Thickness Index, which is the ratio of volume of shell material 

 to internal volume. Such a design provides stability in the substrate by 

 having a great density and low center-of-gravity at the expense of burrowing 

 speed. This is a typical shell structure for suspension feeders, found in 

 stable, firm substrates, which do not frequently change location or reburrow. 

 M. mercenaria is tolerant of an unusually wide range of environmental 

 conditions. It is common in intertidal and shallow subtidal environments. 

 It is found in clean sand and muddy sand, but most commonly in sediments 



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