mantle, and have no tentacles, eyes, "head", or radula. A dorsal ligament, 

 together with teeth formed from the valves, form a hinge. Most are marine. 

 All have a hatchetlike foot and lamellate gills. The Subclass Lamellibranchia 

 has large gills relative to labial palps, forming feeding organs; filaments 

 greatly elongated and reflected, forming 2-sided lamellae, the arms of which 

 usually are united by lamellar junctions. Adjacent filaments are attached by 

 ciliary junctions (filibranch) or united by tissue (eulamellibranch) . Six 

 orders are recognized, differentiated mainly by gill structure and 

 arrangement. Chapter subjects in which M. mercenaria is mentioned are: 

 pathogens of mollusks; hematology; internal defense mechanisms; and 

 aquaculture. Early life history of clams is illustrated briefly by a 

 discussion of embryonic development, induced spawning, artificial rearing 

 of veligers, and pond culture. (Abstracter's note: the statement on p. 277: 

 "Unlike oysters, clams are dioecious." is misleading. Hard clam undergoes 

 sex reversal also.) - J.L.M. 



1227 



Malouf, Robert, Richard Keck, Don Maurer, and Charles Epifanio. 1972. 



Occurrence of gas-bubble disease in three species of bivalve molluscs. 

 J. Fish. Res. Bd. Canada 29(5): 588-589. 



Hard clams held in heated running seawater in winter developed gas bubble 

 disease. Heating cold seawater in closed heat exchangers causes super- 

 saturation with atmospheric gases. The only gross symptom in hard clam was 

 an obvious lightening of gill color, caused by presence of numerous trapped 

 gas bubbles that prevented free flow of blood. Adult hard clams were much 

 less affected than oysters. Clam mortalities were rare. - J.L.M. 



1228 



Manchester, Winnifred B. 1980. 



Quahog dredging is latest career for old dragger . Natl. Fisherman 61(4): 54. 



The Stanley B. Butler, a 90 ft dragger built in Maine in 1938 is making a 

 comeback as a quahog dredger out of Point Judith, R.I. The Butler has been 

 equipped with a jet dredge and brought in a record 90,000 bu of quahogs 

 from waters off Block Island last year. - J.L.M. 



1229 



Mann, R., and T. M. Losordo. 1976. 



The growth of six species of bivalve molluscs in a waste-recycling 

 aquaculture system. In Marine polyculture based on natural food chains 

 and recycled wastes. John H. Ryther. Woods Hole Oceanogr. Inst., Woods 

 Hole, Mass., Tech. Rept. WHOI-76-92. U.S. Dept . Commerce, Natl. Tech. Inf. 

 Serv. PB-261 939: 137-168. 



Only small increments in live weight of Mercenaria mevaenavia were observed 

 from Nov. 1975 to May 1976. Some meat growth was evident at 15° and 20°C. 

 Condition index increased consistently from beginning to end of period. 

 Mortality varied between 15% and 42% in different lots. Results obtained 

 with M. mercenaria and Crassostrea virginiea were termed disappointing. 

 - J.L.M. 



1230 



Mann, Roger, and John H. Ryther. 197 7. 



Growth of six species of bivalve molluscs in a waste recycling-aquaculture 

 system. Aquaculture 11: 231-245. 



Growth of 6 species of bivalve mollusks, including Mercenaria mercenaria, 

 was compared in a waste recycling-aquacultural system. Food was algae, 

 predominantly Phaeodaatylum tricornutum. Experimental temperatures were 

 15° and 20°C, over the period November 1975 to May 1976. M. mercenaria 



344 



