if not the same, to the anti-tumor agent reported by others, because both 

 were obtained by the same extraction procedures, O.D. (optical density?) 

 profiles at 280 my for Sephadex fractions of extracts were almost identical 

 for all preparations, and anti-tumor activity and growth-inhibiting activity 

 were found in equivalent fractions. The authors, however, were unable to 

 obtain a definite dose response curve for anti-tumor activity of clam liver 

 extracts against Bittner mammary tumor. If the growth inhibiting agent is 

 part of a normal control system, tumor cells which have regressed into 

 embryonic types may no longer be sensitive. It was planned to assay this 

 substance against spontaneous mammary tumor. That the growth inhibiting 

 substance from clam livers is part of a mechanism for regulating normal cell 

 growth is suggested by correlation between seasonal variation of inhibitor 

 and clam body weight. Anti-tumor activity was highest in May, but was not 

 assayed for June and July extracts. This did not agree with findings of 

 others. Patterns of anti-tumor activity with season were correlated roughly 

 with erythropoietic inhibiting activity. Clam larva systems were even more 

 sensitive to small amounts of inhibitor, and might provide a good screening 

 system to select extracts for mammalian assays. Results suggest that mammals 

 possess growth regulatory mechanisms not unlike those of invertebrates, if 

 so, this could be a useful therapeutic tool. - from authors' discussion 

 - J.L.M. 



892 



Hutchins, Louis W. 1947. 



The bases for temperature zonation in geographical distribution. Ecol . 

 Monogr. 17(3): 325-335, ill. 



Mercenaria (Venus) mercenaria is not mentioned. - M.W.S. 



893 



Hutchinson, Roger W., and Jens Knutson. 1978. 



Shellfish market review, November 1978. U.S. Dept. Commerce, Natl. Mar. 

 Fish. Serv., Current Economic Analysis S-41: 1-48. 



Gives total landings of clams by species 1960-1977, total landings of hard 

 clams by state 1960-1977, supplies and utilization of clams by species and 

 by month 1977-1978, prices by species by month 1974-1978 (exvessel) , and 

 prices by species by month 1973-1978. - J.L.M. 



894 



Hutton, Robert F. , Bonnie Eldred, Kenneth D. Woodburn, and Robert M. Ingle. 



1956. 



The ecology of Boca Ciega Bay with special reference to dredging and filling 

 operations. Fla. State Bd. Conserv. , Mar. Lab., Tech. Ser. 17(1), 86 p. 



Only 2 specimens of Mercenaria campechiensis were taken at 15 stations. The 

 species obviously was not abundant there. - J.L.M. 



895 



Hyman, Libbie H. 1967. 



The Invertebrates. Vol. 6. Mollusca I. McGraw-Hill, New York, 79 2 p. 



List only. 



896 



Idler, D. R., and U. H. M. Fagerlund. 1955. 



Marine sterols I. Isolation of 24-methylenecholesterol from molluscs. 

 J. Am. Chem. Soc. 77(15): 4, 142-144. 



According to Thompson (1964) abstracted elsewhere in this bibliography, 

 these authors reported 230 mg total cholesterol per 100 g of clam meats 

 (species not given) . - J.L.M. 



249 



