transport by hard clam is largely independent of concentration of particles 

 when only small amounts of suspended matter are present, and also independent 

 of quality of particles with regard to food value. When suspended bentonite 

 concentration varied from 50-1,000 mg/1 there was no observable effect on 

 rate of clearance by Meretrix (Chiba and Oshima 1957). Water is drawn 

 through interf ilamentary slits of bivalves by action of lateral cilia. 

 Particulate matter is retained on the gill, either by directly touching 

 frontal surfaces of filaments, where they are trapped in mucus, or by 

 straining action of large latero-f rontal cilia when these are present. 

 Latero-frontal cilia beat towards the frontal surface of filaments, thus 

 throwing particles on frontal ciliary tracts. Intermittent beating of 

 latero-frontal cilia has been observed in Venus ; resting cilia are stated 

 to form a sieve straining particles from the current passing between 

 filaments, whereas active cilia throw collected particles on to frontal 

 tracts of adjacent filaments (Ansell 1961) . Young larvae of Crassostrea 

 were able to grow only on a few of the algae tested, whereas larvae of 

 M. mercenaria and Mytilus edulis utilized most algae provided they were 

 small enough (Loosanoff and Davis 1963). Apparently possession of thick 

 cell walls reduces food value of algae by making cell contents unavailable. 

 Thus Chlorella and especially Stiahocoaaus often were inferior food as 

 compared with naked flagellates or diatoms. Direct experiments on value of 

 organic detritus as food have been few and difficult to interpret. Loosanoff 

 et al. 1951 obtained only restricted growth in veligers of clam fed on 

 "detritus" from bottom of tidal pools or bottom of a large plankton-culture 

 tank. Growth on a diet of bacteria has been obtained with Mytilus (ZoBell 

 and Landon 1937; ZoBell and Feltham 1938). None of 13 species of marine 

 bacteria was found to be of value as food to veligers of C. vivginica (Davis 

 1953). Allen (1962) found Venus to assimilate 77-95% of 32 P- labelled 

 Nitsschia cells retained by feeding organs; e.g., 23-5% passed out with 

 pseudo- and true feces. Percent assimilated appeared to decrease with 

 increased concentration of algae in water. - J.L.M. 



947 



JjzSrgensen, C. Barker. 1976. 



Comparative studies on the function of gills in suspension feeding bivalves 

 with special reference to effects of serotonin. Biol. Bull. 151(2): 331-343. 



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



948 



JeSrgensen, C. Barker, and Edward D. Goldberg. 1953. 



Particle filtration in some ascidians and lamellibranchs . Biol. Bull. 105(3): 

 477-489. 



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



949 



Joyce, Edwin A., Jr. 1972. 



A partial bibliography of oysters, with annotations. Fla. Dept. Nat. 

 Resources, Mar. Research Lab., St. Petersburg, Spec. Sci. Rept. 34, vi+846 p. 



This extensive bibliography of 4117 titles contains 81 references to Mercenaria 

 meraenaria , 19 to M. campechiensis , 10 to Mercenaria, and one each to M. m. 

 alba, M. m. texana, and M. meretrix, 67 to Venus mercenaria, 10 to Venus, 3 to 

 V. campechiensis , 3 to V. gallina, 3 to V. m. mercenaria, 4 to V. s triatul a , and 

 1 to V. verrucosa, according to the index to taxonomic names issued as a 

 supplement in 197 6. Most of these listings are abstracted in Joyce's 

 bibliography, and all are abstracted in the present bibliography. - J.L.M. 



263 



