were submerged most of the time. At each a strip 3 ft wide and extending at 

 right angles to the tide line was dug clean and planted as follows from low 

 tide shoreward: 4 ft planted with Venus seed at 25/sq ft; 1 ft left 

 unplanted; 4 ft My a. The offshore half of the Venus plants were covered 

 with 3/8" galvanized hardware cloth weighted around the edges. Density of 

 Venus was (clams/ft ) : 



Camp Ribicoff Saunders Point "Walrus" site 



Protected 24 1/2 27 1/2 13 1/2 



Unprotected 26 1/2 16 1/2 8 1/2 



Time elapsed was about 2 months. Data are given also on initial number, 

 final number, mean length and range. Venus was less vulnerable than Mya, 

 but placement may have been the reason. - J.L.M. 



1245 



Marshall, Nelson, and Karen Lukas. 1970. 



Preliminary observations on the properties of bottom sediments with and 

 without eelgrass, Zosteva marina, cover. Proc. Natl. Shellf. Assn. 60: 

 107-111. 



Effects of the eelgrass blight in the early 1930s were not as drastic as 

 had been anticipated. An eelgrass bed, an area cleared of eelgrass, and an 

 open area were compared. Clam diggers were active in the open area, so the 

 open-plot control area probably was turned over about as much as the raked 

 area. At the sediment surface Zosteva areas had higher levels of organic 

 C, higher silt-clay content, and more interstitial water than open areas. 

 Differences between open and Zostera-covered areas were seen only in the 

 top cm layer. In a one-month period no consistent changes were observed 

 from removing eelgrass or raking plots. Differences in hard clam abundance 

 or ecology between areas were not mentioned. - J.L.M. 



1246 



Marteil, L. 1956. 



Acclimatation du clam (Venus mercenavia, L.J en Bretagne. Rev. Trav. Inst. 

 Peches Marit. 20: 157-160. 



According to Heppell (1961) Marteil recorded large hard clams about 20 yrs 

 old in the River Etel, and some as large as 14 cm and up to 500 g in claires 

 of the Gulf of Morbihan and River Penerf, all of which had been laid down in 

 those places before 1940. From ages of clams at Sainte-Avoye, Marteil 

 calculated that years of spawning were years in which mean water temps in 

 July and Aug were above average and at the minimum temp for hard clam 

 breeding. This was taken as possible evidence of local breeding. The 

 substrate at Sainte-Avoye was firm, with oyster shell debris in the mud. -J.L.M. 



1247 



Martin, Arthur W., and Florence M. Harrison. 1966. 



Excretion. In Physiology of Mollusca. Karl M. Wilbur and C. M. Yonge 

 (eds.) Academic Press, New York, Vol. II: 353-386. 



Contains reference to a paper by Kowalevsky (1889) cited elsewhere in this 

 bibliography. - J.L.M. 



348 



