particle sizes ranging from 50 y to 1 mm. Clams were not capable of 

 selecting between different sizes of sand, but did select sand in pre- 

 ference over silt. Clams also selected natural sediments in preference 

 over identical material from which organic matter and micro-organisms had 

 been removed by heating. Experiments also showed that larvae had a strong 

 preference for sediments that had been treated with clam liquor. 

 (Abstracter's note: this paper is so poorly prepared that I had to puzzle 

 over it for some time to extract these conclusions, and I may not have 

 interpreted everything correctly. I noted also that several citations 

 in the text were not in the list of literature cited. For future re- 

 ference, these are: Keck et al. 1971, Wilson 1958, Pratt 1953; there also 

 are several errors in dates, and other missing references not specific 

 to hard clam, which I did not bother to include abovej - J.L.M. 



966 



Keen, A. Myra. 1951. 



Outline of a proposed classification of the pelecypod family Veneridae. Min. 

 Conch. Club S. Calif. 113: (pages not given). 



Accepts separation of Mercenaria from Venus as a distinct genus, based on 

 absence of an anterior lateral hinge tooth, and other relationships. Also 

 places these 2 genera in separate sub-families. - from Wells, Ecology 38(1), 

 1957 - J.L.M. 



967 



Keen, A. Myra. 1971. (With the assistance of James H. McLeanJ 



Marine mollusks from Baja California to Peru. 2nd ed. Sea Shells of 

 Tropical West America, Stanford University Press, Stanford, Calif .: xiv+1064 . 



Genus Mercenaria Schumacher, 1817, Venus of authors. Hinge with a roughened 

 area under the ligament; sculpture predominantly concentric, with fine radial 

 ribs. 464. Mercenaria apodema (Dall, 1902). This resembles the Atlantic 

 M. campechiensis (Gmelin, 1791) but is a creamy white, has rounded concentric 

 ribs that are not lamellar, and has a narrower roughened area on the hinge. 

 Length 47 mm; height 4 3 mm; diameter 28 mm. A single valve was collected 

 nearly a century ago at Panama, and the species has not since been reported 

 in the literature. A complete specimen in the Stanford University collection 

 that matches well the original figure and description was found in the 1940s 

 by Mr. A. Sorensen at Guaymas, Mexico. Unfortunately, this specimen was not 

 taken alive, so that positive proof has yet to be furnished for the 

 occurrence of Mercenaria in the Panamic province. - J.L.M. 



968 



Keen, A. Myra, and Don L. Frizzell. 1939. (Second Printing. 1946.) 



Illustrated key to west North American Pelecypod genera. Stanford University 

 Press, Stanford, Calif., 30 p. 



Mercenaria is the only representative of the genus. - J.L.M. 



969 



Keep, Josiah. 1901. 



Exotic mollusks in California. Nautilus 14(10): 114-115. 



On the Alameda shore of San Francisco Bay several dead valves of Venus 

 mercenaria were collected. Living specimens were not found, but it was the 

 author's opinion that live quahogs would be found in deeper water. - J.L.M. 



970 



Kehr, Robert W. , Benjamin S. Levine, C. T. Butterf ield, and Arthur P. Miller. 

 1941. 



A report on the public health aspects of clamming in Raritan Bay. Fed. 

 Security Agency, U.S. Public Health Serv. , District No. 1, iv+119 p. 



The survey was made at request of N.Y. State Conservation Dept. for a ruling 



268 



