There are 10 specimens from 4 samples of this rather rare 

 species in the NEFC collection (Table 5). 



Our samples are from the upper continental slope between 

 Delaware Bay and Cape Hatteras, N.C. (Fig. 52; Theroux and 

 Wigley footnote 4, table 86). 



Johnson (1934) and Abbott (1974) reported a depth occur- 

 rence of 361 m for this species. 



Our samples are from between 1,100 and 1,800 m in depth 

 with a mean of 1,540 m. This depth range places all samples 

 and specimens in the 1,000-1,999 m depth range grouping 

 (Table 70). 



Our samples occurred in three sediment types: silty sand, 

 silt, and clay. Fifty percent of the samples and 20% of the 

 specimens occurred in silt while each of the remaining two 

 types, silty sand and clay, contained 25% of the samples and 

 40% of the specimens (Table 71). 



Limopsis cristata Jeffreys 1876. Cristate limopsis. Figure 52. 



The distribution of this species is from Cape Cod. Mass., to 

 southeast Florida (Johnson 1934; Abbott 1974). It is also 

 found in the Caribbean and western Europe (Clarke 1962). 



This species which is commonly dredged off Florida, is 

 represented by four specimens from three samples in our 

 collection (Table 5). 



Our samples are from continental slope waters south of 

 Georges Bank with one inshore sample north of Jacksonville, 

 Fla. (Fig. 52; Theroux and Wigley footnote 4, table 87). 



Johnson (1934) reported a depth distribution of 156 to 2,004 

 m, while Clarke (1962) reported a depth range of 1 17 to 5,014 

 m. 



Our samples are from water depths ranging from 8 to 1 ,625 

 m with a mean of 699 m. Thirty-three percent of the samples 

 and 25% of the specimens are in the 0-24 m and 200-499 m 

 depth range groupings; whereas, 33% of the samples and 50% 

 of the specimens are in the 1 ,000-1 ,999 m grouping (Table 72). 



Two of our samples occurred in silty sand accounting for 

 67% of the samples and 50% of the specimens, and one sample 

 or 33% of the samples occurred in silt which contained 50% of 

 the specimens (Table 73). 



Limopsis minuta Philippi 1836. Minute limopsis. Figure 53. 



The distribution of this species ranges from Newfoundland 

 to both sides of Florida (Johnson 1934; La Rocque 1953; 

 Morris 1973; Abbott 1974). Ockelmann (1958) and Clarke 

 (1962) reported on the distribution of this species for Arctic 

 and European regions where it is fairly widespread, including 

 the Canary Islands and the Mediterranean. 



Limopsis minuta is represented by 30 specimens from 13 

 samples in the NEFC collection (Table 5). 



Of the 13 samples in the NEFC collection, 1 is in the Gulf of 

 Maine, the remainder are on the upper continental slope 

 between Browns Bank and Chesapeake Bay (Fig. 53; Ther- 

 oux and Wigley footnote 4, table 88). 



The minute limopsis is a deep water species which ranges 

 between 55 and 5,014 m depth (Clark 1962). 



Our samples range from 16 to 1 .660 m in depth with a mean 

 of 1,038 m. Sixty-two percent of the samples and 60% of the 

 specimens are in the 1 ,000- 1 ,999 m depth range grouping; 23% 

 of the samples and 33% of the specimens are in the 500-999 m 

 grouping and both the 200-499 m and 0-24 m groupings contain 

 8% of the samples and 3% of the specimens (Table 74). 



Two sediment types, silty sand and silt, each yielded 31% of 

 the samples but 23 and 17% of the specimens, respectively; 

 however, clay accounted for 23% of the samples and 37% of 

 the specimens; it was found in one other sediment type within 

 our study area, sand-gravel, which contained 8% of the sam- 

 ples and 3% of the specimens (Table 75). 



Limopsis sulcata Verrill and Bush 1898. Sulcate limopsis. Fig- 

 ure 53. 



This species is reported to occur from Cape Cod. Mass., to 

 Florida; it ranges into the Gulf States and the West Indies 

 (Johnson 1934; Morris 1973; Abbott 1974). 



The NEFC collection contains 21 specimens from 6 sam- 

 ples of this common species (Table 5). 



Our samples are located at the continental shelf break and 

 on the upper continental slope between Nova Scotia and 

 Hudson Canyon (Fig. 53; Theroux and Wigley footnote 4, 

 table 89). 



The sulcate limopsis is a moderately shallow to deep water 

 inhabitant occupying depths between 80 and 639 m (Abbott 

 1974; Porter 1974). 



Our samples are from water depths ranging between 93 and 

 1.934 m with a mean of 1.406 m. The 50-99 m depth range 

 grouping contains 17% of the samples and 48% of the speci- 

 mens, while the 1.000-1,999 m grouping contains 83% of the 

 samples and 52% of the specimens (Table 76). 



Our samples were obtained from three sediment types: silty 

 sand, silt, and clay, each of which contained 33% of the 

 samples but 14. 33, and 52% of the specimens, respectivelv 

 (Table 77). 



Limopsis sp. Figure 53. 



The NEFC collection contains two specimens from two 

 samples of this genus (Table 5). 



Our samples are located on the upper portion of the con- 

 tinental slope south of Cape Cod. Mass. (Fig. 53; Theroux and 

 Wigley footnote 4, table 90). 



The samples are from 400 and 1,550 m water depth. Fifty 

 percent of both samples and specimens are in the 200-499 m 

 depth range grouping: the remaining 50% of the samples and 

 specimens are in the 1.000-1.999 m grouping (Table 78). 



Our samples were obtained from silty sand and silt sedi- 

 ments, each of which contained one sample and one specimen 

 (Table 79). 



Family GLYCYMERIDIDAE 

 Genus Glycymeris Costa 1778 



Glycymeris americana (DeFrance 1829). Giant American bit- 

 tersweet. Figure 46. 



This species occurs from North Carolina to Florida; it also 

 occurs in the West Indies, Texas, and Brazil (Johnson 1934; 

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

 Although Morris' (1973) work includes the distribution of the 

 other authors, he extended it northward to include Virginia. 



Glycymeris americana is a relatively rare bivalve repre- 

 sented in our collection by one specimen from one sample 

 (Table 5). 



14 



