was obtained from Long Island Oyster Farms. Although dry meat weight more 

 than doubled at some positions, and growth was greater than previously 

 reported, it was considerably less than that of Tapes japonica under 

 identical conditions. It was suggested that hard clam has little 

 potential for culture in the present system. - J.L.M. 



1231 



Manning, J. R. 1935. 



Fish and shellfish for food. U.S. Bu. Fish., Spec. Memo 2256B. 



Cited in Tressler and Lemon (1951) with data on vitamin content, protein and 

 fat in clams (species not named) . - J.L.M. 



1232 



Mansour, K. 1946. 



Food and digestive organs of lamellibranchs. Nature 158(4011): 378. 



The author takes issue with certain conclusions of C. M. Yonge, about the 

 fate of chlorophyll in blood and lumen of the gut, about the function of the 

 crystalline style, about identity of phagocytes, and about animal matter in 

 the gut. Meroenaria (Venus) meroenaria is not mentioned. There follows a 

 comment by J. J. Mansour-Bek, entitled "Extracellular proteolytic and 

 lipolytic enzymes of some lamellibranchs" which also has been cited 

 separately in this bibliography. - J.L.M. 



1233 



Mansour-Bek, J. J. 1946. 



Extra-cellular proteolytic and lipolytic enzymes of some lamellibranchs. 

 Nature 158: 378-379. 



Follows a short paper by K. Mansour, abstracted also in this bibliography, 

 and comments on observations by C . M. Yonge on the origin of extracellular 

 proteolytic and lipolytic enzymes in stomachs of lamellibranchs. - J.L.M. 



1234 



Manwell, Clyde. 1963. 



The chemistry and biology of hemoglobin in some marine clams - I. 

 Distribution of the pigment and properties of the oxygen equilibrium. 

 Comp. Biochem. Physiol. 8(3): 209-218. 



Most lamellibranch mollusks lack respiratory pigments. Hemocyanin is not 

 found in clams, but adductor muscles of Meroenaria meroenaria are pale pink 

 with low concentrations of muscle hemoglobin (myoglobin) . The oxygen 

 affinity of hard clam myoglobin is very high (P5q=0.55 mm Hg) . Clam 

 hemoglobin lacks the sigmoid oxygen equilibrium curve typical of many 

 vertebrate and a few annelin hemoglobins. This means there are no 

 strong positive interactions between oxygen-combining centers. Hard clam 

 myoglobin has n=1.00, which is to be expected of a hemoglobin with a 

 molecular weight corresponding to only one heme per molecule. If one 

 considers tissue hemoglobins to function simply as stores of oxygen it is 

 difficult to understand the significance of most clam tissue hemoglobins, 

 for only those of Tivela and shipworms are present in high enough 

 concentration to give more than a light color to tissues. However, the 

 very high affinity of M. meroenaria muscle hemoglobin for oxygen may serve 

 to facilitate diffusion of oxygen into that thick, non-vascular structure. 

 In small clams, muscles are almost colorless, but in clams over 8-10 cm 

 long muscles are a deep pink. M. meroenaria has higher concentrations of 

 hemoglobin in adductor muscles than M. oampeohiensis , even when identical 

 clams of the two species are raised side by side. Myoglobins of the two 

 are identical in solubility and electrophoretic properties. All except a 

 few large M. meroenaria have no readily detectable hemoglobin in heart 

 muscle, but heart of M. oampeohiensis has a higher concentration of 



345 



