sand; mixtures of silty mud, sand, and oyster shells; and gravel. Shell and 

 sandy mud contained significantly higher clam densities than other substrates. 

 Most clams were larger than 3 in, which was interpreted as an indication of 

 a declining population, yet abundance per unit area in Rehoboth Bay was 

 higher than in a 196 8 survey, and in Indian River Bay about the same. It was 

 suggested, however, that sampling was more efficient in 1976. It was 

 estimated that 67,412 recreational clammers used the 2 bays from 1 Apr to 

 31 Oct 1976. Based on age estimates the dominant size classes taken in 1976 

 were the same year classes that dominated the 1968 survey. It was concluded 

 that recruitment has been poor in the interim. No relationship between 

 water depth and clam abundance was seen. It was recommended that a 675-acre 

 tract in the shell area of Rehoboth Bay be set aside and managed by the 

 State as a dredging area. A daily catch limit of 2,500 clams also was 

 recommended. Dredging should not begin until after the spawning season. No 

 new leasing should be permitted. - J.L.M. 



372 



Cole, W. H. 1940. 



The composition of fluids and sera of some marine animals and of the sea 

 water in which they live. J. Gen. Physiol. 23: 575-584. 



Mantle fluid of Venus mercenaria from Me. had pH 7.90, -A 1.760, Na/Cl 

 0.856, K/Cl 0.0144, Ca/Cl 0.0185, Mg/Cl 0.0486, and S0 4 /C1 0.0496; from 

 Delaware Bay: pH 7.65, -A° 1.369, Na/Cl 0.799, K/Cl 0.0182, Ca/Cl 0.0298, 

 Mg/Cl 0.0799, S04/C1 0.0515. Blood of V. mercenaria from Delaware Bay 

 had pH 7.68, -A° 1.386, Na/Cl 0.826,. K/Cl 0.0184, Ca/Cl 0.0302, Mg/Cl 

 0.0778, and S0 4 /C1 0.0508. Seawater from the two localities had pH 8.10 

 and 8.01, respectively, -A° 1.759 and 1.336, Na/Cl 0.861-0.931 and 0.878, 

 K/Cl 0.0173-0.0188 and 0.0232, Ca/Cl 0.0195-0.0197 and 0.0169, Mg/Cl 

 0.0687-0.0140 and 0.0984, SO4/CI 0.0516-0.0629 and . 0514, respectively. 

 Animals examined fell into 4 groups according to composition of body 

 fluid compared to that of external medium. Venus and some echinoderms 

 fell in a group with ionic ratios of 1.0*0.1, except for the unexplained 

 low ratio of 0.74 for Mg in mantle fluid of Venus. Venus collected from 

 brackish water had significant differences from those living in seawater. 

 All fluids were hypertonic to the external medium, even the mantle fluid, 

 in material from Delaware Bay. Composition of mantle fluid and blood of 

 Venus was identical within the experimental error, each containing more 

 calcium than Bay water. Living conditions for hard clam are less favorable 

 in Delaware Bay than in pure seawater, and it is likely that increased Ca 

 content is caused by solution of CaC0 3 from valves. pH of all fluids was 

 below that of seawater. Increased osmotic pressure of sera of animals in 

 brackish water was caused by unequal accumulation of Na, K, Ca, and CI ions. 

 SO4 and Mg ionic ratios did not change. - J.L.M. 



373 



Collins, J. W., and Hugh M. Smith. 1892. 



A statistical report on the fisheries of the Gulf states. Bull. U.S. Fish 

 Comm. for 1891, Vol. XI (1893): 93-184. 



No mollusks other than American oyster had yet attained economic importance, 

 although in Florida Venus meraenaria was taken in small quantities. In 1890 

 Fla. reported 7,330 lbs of hard clams landed, with a landed value of $747. 

 This was 733 bu of clams. The same figures were reported for 1889. By 

 counties, estimates were the same in both years: 1,3 30 lbs in Monroe County; 

 1,330 in Lee; 1,340 in Hillsboro; and 3,330 in Levy; all on the west coast. 

 Gear used was not specified. - J.L.M. 



374 



Colton, Harold Sellers. 1908. 



How Fulgur and Syeotypus eat oysters, mussels and clams. Proc. Acad. Nat. 

 Sci. Phila. 60: 3-10, 5 pis. 



103 



