937 



Johnson, William H. , Joseph S. Kahn,and Andrew G. Szent-Gyorgyi . 1959. 



Paramyosin and contraction of "catch muscles". Science 130(3368): 160-161. 



Isotonic shortening of glycerol-extracted preparations of catch muscles of 

 Venus mercenaria and Mytilus edulis was inhibited at pHs and ionic strengths 

 at which extracted paramyosin crystallizes. Isometric tension development is 

 scarcely altered under the same conditions. The "catch" mechanism is 

 explained as crystallization of paramyosin, which "freezes" the muscle at any 

 length or in any state, inhibiting shortening and increasing resistance to 

 stretch. It is assumed that actomyosin and paramyosin are at least 

 functionally separated in catch muscles. - modified authors' abstract - J.L.M. 



933 



Johnston, Richard L., and Albert F. Eble. 1972. 



Histology, histochemistry, and biochemistry of the digestive gland of 

 Mercenaria mercenaria (Bivalva) . Bull. N.J. Acad. Sci. 17(2): 44. 



Sections of digestive gland of M. mercenaria had ciliated ducts of 2 sizes, 

 a larger main duct and a smaller pre-tubular duct. Smaller ducts ultimately 

 terminated in tubules, where final stages of digestion occur. The transition 

 zone between pretubular duct and tubule was very abrupt; duct cells were 

 eosinophilic, columnar, and had several nucleoli in the spherical nucleus; 

 tubule cells were cuboidal and basophilic, usually with a single prominent 

 nucleolus. Distribution and content of acid phosphatase, x-amylase, and 

 non-specific esterase in the digestive gland also were studied, but not 

 described. - J.L.M. 



939 



Johnstone, Kathleen Yerger. 1957. 



Sea Treasure. A Guide To Shell Collecting. Houghton Mifflin Co. , Boston. 

 The Riverside Press, Cambridge, ix+242 p. 



Pearls produced by Mercenaria mercenaria and some other mollusks are of no 

 value. Purple or white pearls sometimes produced by M. mercenaria look like 

 purple and white beads, but have no luster. The name Mercenaria came from 

 Indian use of quahogs as money. Indians made "peak", "wampumpeak" , "runtees" 

 of 2 kinds, and "pipes". Peak was made from white part of shell, wampumpeak 

 from the purple border. This "famous purple wampum" was twice as valuable as 

 peak. These 2 types were exactly alike except in color. Each piece was 

 shaped like a tube, one inch long or less, and about 1/8 inch in diameter. 

 These were first made around Narragansett Bay and Long Island Sound, and were 

 sometimes called "sewan". Runtees were oval beads drilled lengthwise, or 

 flat round buttons drilled edgewise. Pipes were shaped like peak, but were 

 2 to 3 inches long and greater in diameter. Eventually, wampum made from 

 M. mercenaria replaced other kinds of shell money in the southeast. Shell 

 money was strung, and was measured by cubits, the distance from tip of little 

 finger to elbow. English traders valued wampumpeak at 18 pence/yd and peak 

 at ninepence. VJhen some Dutch and English traders found out how to make 

 counterfeit wampum the market was flooded with it, and shell wampum soon 

 disappeared from trade. - J.L.M. 



940 



Jones, R. D., L. D. Jensen, and R. W. Koss. 1974. 



Benthic invertebrates. In Environmental responses to thermal discharges 

 from the Indian River Station, Indian River, Delaware. Rept. 12 to Electric 

 Power Research Institute, Palo Alto, Calif., EPRI Pub. 74-049-00-3: 106-126. 



Mercenaria mercenaria was found in small numbers only in downstream stations, 

 below the discharge canal. It ranked 78 in order of abundance among 97 

 species or groups of species collected. Details by station are given in 

 appendices C & D, pages 183-196 of the entire report. - J.L.M. 



261 



