atlantic, Caribbean, and Boreal provinces and mentioned that 

 it has been introduced into British waters. 



As previously mentioned, this organism is primarily subtid- 

 al but ranges out to moderately shallow water. In the southern 

 reaches of its range it does occur intertidally. The sample 

 containing the one specimen of the American oyster in our 

 collection is from a depth of 1 m. 



Our sample has no sediment data associated with it. 

 However, due to the life habits of the organism, it is normally 

 found on hard bottom as a result of its habit of attaching itself 

 to the substratum. 



Subclass HETERODONTA 

 Order VENEROIDA 

 Family LUCINIDAE 



The NEFC collection contains 166 specimens from 44 sam- 

 ples which are identified to the level of family Lucinidae 

 (Table 5). 



Samples containing members of this family occur in the 

 middle and southern reaches of our study area from Chesa- 

 peake Bay southward to just north of Miami, Fla.; however, 

 there is one sample from Buzzards Bay, Mass., which con- 

 tains some members of this family (Fig. 56; Theroux and 

 Wigley footnote 4, table 95). 



Our samples range in depth from 4 to 53 m with a mean of 18 

 m. The majority of samples and specimens are in the shal- 

 lowest depth range grouping, 0-24 m, which contains 82% of 

 the samples and 93% of the specimens; 14% of the samples 

 and 5% of the specimens are in the 25-49 m depth range 

 grouping, and 5% of the samples and 1% of the specimens are 

 in the 50-99 m grouping (Table 132). 



Sand was the predominant substrate in which members of 

 the family Lucinidae were found. This substrate contained 

 73% of the samples and 87% of the specimens; the next 

 preferred substrate type was sand-shell which contained 23% 

 of the samples and 1 1% of the specimens. Each of the follow- 

 ing sediment types, shell and silty sand, contained 2.3% of the 

 samples and 1.2 and 0.6% of the specimens, respectively 

 (Table 133). 



Genus Lucinoma Dall 1901. Figure 54. 



Lucinoma blakeana Bush 1893. 



Our samples occurred in sand and silty sand substrates, 

 each of which contained 50% of the samples, but 38 and 62% 

 of the specimens, respectively (Table 135). 



Lucinoma filosa (Stimpson 1851). Northeast lucina. Figure 55. 



The northeast lucina has a fairly wide distribution ranging 

 from Newfoundland to northern Florida and on to the Gulf 

 States (Johnson 1934; Ockelmann 1958; Morris 1973; Abbott 

 1974). 



This is a common offshore species having a fairly strong 

 representation in the NEFC collection which contains 2,266 

 specimens from 241 samples (Table 5). 



Samples in the NEFC collection occur throughout the 

 study area; however, there is a greater concentration in the 

 Southern New England shelf and slope region (Fig. 55; Ther- 

 oux and Wigley footnote 4, table 93). 



The zoogeographic distribution of this species is Boreal, 

 Virginian, and Caribbean (Coomans 1962). 



The northeast lucina is a moderately deep dwelling bivalve 

 occupying water depths between 29 and 966 m (Johnson 

 1934). Morris ( 1973) stated that there is an increase in depth in 

 which this species is found with a decrease in latitude. 



Our samples are from water depths ranging between 15 and 

 1,408 m with a mean of 147 m. The majority of both samples 

 and specimens are from mid-depth regions represented by the 

 50-99 m depth range grouping which contains 45% of the 

 samples and 32% of the specimens and the 100-199 m grouping 

 with 38 and 51%, respectively. Significantly smaller amounts 

 of both samples and specimens occur in other depth range 

 groupings (Table 136). 



The northeast lucina was absent from coarser grained sub- 

 strates but occurred in sand, sand-shell, and finer substrates. 

 Sand yielded 42% of the samples and 39% of the specimens, 

 silty sand 37% of the samples and 48% of the specimens. 

 Other substrates in which this species was found were clay, 

 with 14% of the samples and 11% of the specimens, silt with 

 5% of the samples and 1% of the specimens, and sand-shell 

 with 2% of the samples and 0.4% of the specimens (Table 

 137). 



Lucinoma sp. Figure 55. 



This species occurs from Massachusetts Bay to off Cape 

 Fear, N.C. (Johnson 1934; Abbott 1974). 



Lucinoma blakeana is represented in the NEFC collection 

 by 34 specimens from 6 samples (Table 5). 



Our samples are from the continental shelf in the Middle 

 Atlantic Bight region off New York (Fig. 54; Theroux and 

 Wigley footnote 4, table 92). 



The bathymetric range of this species is from 33 to 849 m 

 depth (Johnson 1934; Abbott 1974). 



Our samples occupy a depth range of between 84 and 266 m 

 with a mean of 142 m. Fifty percent of the samples and 38% of 

 the specimens are in the 50-99 m depth range grouping, while 

 33% of the samples and 59% of the specimens are in the 

 100-199 m grouping; 17% of the samples but only 3% of the 

 specimens are in the deepest depth range grouping, 200-499 m 

 (Table 134). 



The NEFC collection contains four specimens from four 

 samples which bear the designation Lucinoma sp. (Table 5). 



Members of the genus Lucinoma in our collection are from 

 the continental shelf region in the Gulf of Maine and on the 

 continental slope south of the Northeast Peak of Georges 

 Bank (Fig. 55; Theroux and Wigley footnote 4, table 94). 



Our samples are from depths which range between 23 and 

 1,240 m with a mean of 554 m. Twenty-five percent of the 

 samples and 25% of the specimens occur in each of the follow- 

 ing four depth range groupings: 0-24, 200-499, 500-999, and 

 1,000-1,999 m (Table 138). 



Members of the genus Lucinoma were found in two sedi- 

 ment types, silty sand and silt which contained, with regard to 

 both samples and specimens, 75% of each in the former and 

 25% of each in the latter (Table 139). 



25 



