Members of this family are distributed in the Virginian, 

 Carolinian, and Caribbean provinces in the western Atlantic 

 and in the Celtic province in Europe (Coomans 1962). 



Samples in our collection containing this taxon range from 

 13 to 3,820 m in depth, this range includes the deepest sam- 

 pling site in our database, the mean depth is 615 m. The 0-24 m 

 depth range grouping contains 43% of the samples and 53% of 

 the specimens; the 50-99, 100-199, 200-499, and 2,000-3,999 m 

 depth range groupings each contain 14% of the remaining 

 samples; specimen density in the above groupings is 13, 7, 7, 

 and 20%, respectively (Table 58). 



Fourteen percent of the samples containing Arcidae oc- 

 curred in each of the following sediment types (percent speci- 

 mens in parentheses): gravel (7), sand-gravel (7), till (7), silty 

 sand (20), and clay (13). Sand contained 29% of the samples 

 and 47% of the specimens (Table 59). 



Genus Anadara Deshayes 1830. 



Anadara ovalis (Bruguiere 1789). Blood ark. Figure 4. 



The blood ark is distributed from Massachusetts to the Gulf 

 States; it also occurs in the West Indies and Brazil (Morris 

 1973; Abbott 1968, 1974; Emerson et al. 1976). 



There are three samples containing three specimens of this 

 species in our collection (Table 5). It is considered to be 

 common to very abundant within its range (Abbott 1968, 

 1974; Dance 1974). 



Our samples are from Woods Hole, Mass., on the southern 

 Rhode Island shore, and east of Atlantic City, N.J. (Fig. 4; 

 Theroux and Wigley footnote 4, table 6). 



The main distribution is Transatlantic and Caribbean 

 (Dance 1974). 



The reported depth distribution for this species is from 0.3 

 to 31 m (Abbott 1968; Porter 1974). 



Our samples range in depth from to 24 m with a mean 

 depth of 8 m. 



Two samples containing A. ovalis were in a sand substra- 

 tum, while the third was unclassified with regard to sediment 

 type. 



Anadara transversa (Say 1822). Transverse ark. Figure 4. 



The transverse ark is reported to occur from Massachusetts 

 to Florida, and is also found in Texas, the West Indies, and the 

 Caribbean (Johnson 1934; Abbott 1968, 1974: Morris 1973; 

 Emerson et al. 1976). 



There are 6 samples containing 17 specimens of this fairly 

 common species in our collection (Table 5). 



Our samples are from off the New England coast with one 

 sample in the shoal region of Georges Bank and the remainder 

 in Vineyard Sound and at the entrance to Long Island Sound 

 (Fig. 4; Theroux and Wigley footnote 4, table 7). 



The main distribution of this species is Virginian and 

 Carolinian in the western Atlantic, and Celtic in Europe for 

 the family (Coomans 1962): Gosner (1971) listed it as Virgi- 

 nian, and Dance (1974) as Transatlantic and Caribbean. 



The bath\ metric distribution of the transverse ark is from 

 below low water to about 37 m. (Abbott 1968. 1974; Porter 

 1974). 



The depth range of our samples is from to 37 m with a 

 mean of 12 m. The 0-25 m depth range grouping contains 83% 



of the samples and 94% of the specimens while the remaining 

 17 and 6%, respectively, are in the 25-49 m grouping. 



Anadara transversa is found on rocks in sandy mud. and in 

 sandy and mud bottoms (Abbott 1968. 1974; Morris 1973; 

 Emerson et al. 1976). 



One of our samples containing two specimens was obtained 

 from a silty sand substratum; the remainder of our samples 

 were unclassified with regard to sediment type. 



Genus Area Linne 1758 

 Area sp. Figure 7. 



There are 1 1 samples in our collection containing 19 speci- 

 mens of the genus Area (Table 5). 



All of our samples occur between Cape Hatteras, N.C. , and 

 Miami, Fla. (Fig. 7; Theroux and Wigley footnote 4. table 10). 

 Although the distribution chart shows only nine locations for 

 this genus, one of the sampling sites yielded three replicate 

 samples containing specimens. 



This genus is Virginian. Carolinian, and Caribbean in dis- 

 tribution (Coomans 1962). 



Our samples range from 6 to 852 m in depth with a mean of 

 192 m. The majority of samples (36%) and specimens (37%) 

 are in the 25-49 m depth range grouping. The 0-24 and 500-999 

 m groupings contain 27 and 18% of the samples and 26 and 

 21% of the specimens, respectively; both the 50-99 and 200- 

 499 m groupings contain 9% of the samples but 5 and 1 1% of 

 the specimens, respectively (Table 60). 



Members of the genus Area were found in four sediment 

 types: 45% of the samples and 47% of the specimens occurred 

 in sand with lesser amounts occurring in sand-shell, silty 

 sand, and silt substrates (Table 61). 



Genus Bathyarca Kobelt 1891 

 Bathyarca anomala (Verrill and Bush 1898). Figure 18. 



Both Johnson's (1934) and Abbott's (1974) information 

 concerning this species is the reiteration of that provided by 

 Verrill and Bush (1898) that it occurs off Cashes Ledge in the 

 Gulf of Maine at 49 m depth. 



There are 9 samples containing 129 specimens of this small 

 bivalve in our collection (Table 5). 



Our samples are all from the Gulf of Maine and at the mouth 

 of the Bay of Fundy (Fig. 18; Theroux and Wigley footnote 4, 

 table 29). 



The samples in our collection range from 73 to 234 m in 

 depth with a mean of 147 m. The majority of both samples and 

 specimens, 44 and 58%, respectively, are in the 100-199 m 

 depth range grouping; lesser amounts, 22% of samples and 

 39% of specimens, are in the 50-99 m grouping, and 33% of 

 samples but only 3% of specimens are in the 200-499 m group- 

 ing (Table 62). 



The majority of our samples and specimens were found in 

 till substrates, 38 and 90%, respectively; 25% of the samples 

 and 4% of specimens were in clay, while sand-gravel, sand, 

 and silty sand sediments each contained 13% of the samples 

 and from 4 to 2% of the specimens (Table 63). One sample 

 containing 72 specimens is unclassified with regard to sedi- 

 ment type. 



12 



