The NEFC sample is from the continental shelf east of 

 Jacksonville, Fla. (Fig. 46; Theroux and Wigley footnote 4, 

 table 76). 



This species is found in moderately shallow water ranging 

 from 2 to 119 m in depth (Johnson 1934; Abbot 1974). Our 

 sample is from 24 m. placing it in the 0-24 m depth range 

 grouping. 



The substrate type for our sample is sand. 



Glycymeris pectinata (Gmelin 1791). Comb bittersweet. Figure 

 47. 



The known distribution of this species is from the Carolinas 

 to Florida, the West Indies, onward to Texas and Mexico, and 

 south to Brazil (Johnson 1934; Abbott 1968, 1974; Morris 

 1973; Emerson et al. 1976). 



The comb bittersweet is a common to moderately common 

 bivalve species of the U.S. east coast; the NEFC collection 

 contains 40 specimens from 20 samples (Table 5). 



Our samples are from the continental shelf ranging from 

 Cape Fear, N.C., south to the southern tip of Florida with a 

 moderate gap in the latitude of Charleston, S.C. (Fig. 47; 

 Theroux and Wigley footnote 4, table 77). 



Dance (1974) placed this species in the Caribbean zoogeo- 

 graphic province. 



The bathymetric range of this species is from shallow to 

 moderately deep water which ranges from 4 to 320 m (Johnson 

 1934). 



Our samples range from 12 to 1 12 m in depth with a mean of 

 40 m. The majority of samples (55%) and specimens (38%) are 

 in the 25-49 m depth range grouping with 30% of the samples 

 and 30% of the specimens in the 0-24 depth range grouping; 

 15% of the samples, and 33% of the specimens are in the 

 100-199 m depth range grouping (Table 80). 



This species is found on sand and gravel bottom (Abbott 

 1968; Morris 1973; Emerson et al. 1976). 



Our samples occurred in sand-gravel, sand-shell, sand, and 

 silty sand substrates. There were more samples (50%) in sand 

 than specimens (30%); however, sand-shell substrates con- 

 tained 40% of the samples and 55% of the specimens; sand- 

 gravel and silty sand each contained 5% of the samples but 10 

 and 5%, respectively, for specimens (Table 81). 



Glycymeris sp. Figure 48. 



The NEFC collection contains 48 specimens of bivalves 

 from 23 samples which have been classified to the generic 

 level Glycymeris sp. (Table 5). 



Samples of this taxon are from the continental shelf and 

 slope between Cape Fear, N.C., and Key West, Fla. (Fig. 48; 

 Theroux and Wigley footnote 4, table 78). 



Our samples range in depth from 10 to 580 m of water with a 

 mean of 133 m. Thirty-nine percent of the samples and 42% of 

 the specimens are in the 25-49 m depth range grouping; 30% of 

 the samples and 23% of the specimens are in the 200-499 m 

 grouping; 22% of the samples and 29% of the specimens are in 

 the 0-24 m depth range grouping; the 100-199 m and the 

 500-999 m groupings each contain 4% of the samples and 2 and 

 4% of the specimens, respectively (Table 82). 



Our samples occurred in three sediment types, shell, sand- 

 shell, and sand. Sand was the predominant substrate, contain- 

 ing 74 and 83% of samples and specimens, respectively ; sand- 



shell contained 22% of samples and 15% of the specimens, 

 while shell contained 4 and 2%, respectively (Table 83). 



Order MYTILOIDA 

 Family MYTILIDAE 



The NEFC Specimen Reference Collection contains 201 

 specimens of members of the family Mytilidae which were 

 obtained from 33 samples (Table 5). 



Samples containing members of the mussel family range 

 from offshore Nova Scotia south through the Gulf of Maine 

 onto the Southern New England continental shelf and slope 

 off Atlantic City, N.J., and Delaware Bay (Fig. 69; Theroux 

 and Wigley footnote 4, table 119). 



The range in depth for these samples is 15 to 564 m with a 

 mean of 139 m. The majority of both samples and specimens 

 are in the 100-199 m depth range grouping which contains 36 

 and 49%, respectively; the 50-99 m grouping contains 21% of 

 the samples and 18% of the specimens, while the 200-499 m 

 grouping contains 24% of the samples and 8% of the spe- 

 cimens; the 25-49 m grouping contains 6% of the samples and 

 21% of the specimens; the 0-24 m and 500-599 m groupings 

 contain 9 and 3%, respectively, for samples and 2% each of 

 specimens (Table 84). 



Members of this taxon were obtained from all sediment 

 types considered in this report except shell. Abundance in 

 terms of decreasing sediment particle size was 8% of the 

 samples and 20% of the specimens in gravel; 12 and 42%, 

 respectively, in sand-gravel; 8 and 2%, respectively, in till; 4 

 and 14%, respectively, in sand-shell; 19 and 3%, respectively, 

 in sand; 8 and 8%, respectively, in silty sand; 15% of the 

 samples and 6% of the specimens occurred in silt, and 27 and 

 5%, respectively, occurred in clay (Table 85). There are 7 

 samples containing 30 specimens which are unclassified with 

 regard to sediment type. 



Genus Brachidontes Swainson 1840 



Brachidontes exustus (Linne 1758). Scorched mussel. Figure 21. 



This mussel is distributed from Cape Hatteras, N.C., to 

 Texas and the West Indies, and Brazil to Uruguay, and is 

 often locally abundant (Morris 1973; Abbott 1974). 



Our collection contains 12 specimens from 2 samples of this 

 species (Table 5). Abbott ( 1974) noted that this species prefers 

 brackish waters. 



One of our samples is from north of Charleston, S.C, and 

 the other north of Jacksonville, Fla. (Fig. 21; Theroux and 

 Wigley footnote 4, table 33). 



This species, which is normally found on rocks and pilings 

 and commonly found washed ashore on shells and seaweed 

 (Abbott 1974), also occurs in moderately shallow water (Mor- 

 ris 1973). Our samples are from 5 and 6 m of water. 



One sample containing six specimens was obtained from a 

 sand substratum while the second, also with six specimens, 

 was from a silty sand sediment. 



Genus Crenella Brown 1827 



Crenella decussata (Montagu 1808). Decussate crenella. Figure 

 31. 



This species is thought to be continuously circumpolar and 



15 



