are in the 50-99 m depth range grouping; abundance of both 

 samples and specimens diminishes with increasing and de- 

 creasing depth range beyond this range (Table 242). Eleven 

 samples containing 143 specimens are lacking information 

 with regard to depth. 



It has been reported that the ocean quahog is found on 

 sandy mud substrates in the western Atlantic (Abbott 1974), 

 and on firm bottoms of sand and muddy sand in the eastern 

 Atlantic (Tebble 1966). 



Fifty-six percent of our samples occurred in sand, 12% in 

 clay, and 9% in silty sand. In terms of density 43% of the 

 specimens occurred in clay, 32% in sand, and 12% in silty 

 sand. Other sediment types provided 6% or less of both 

 samples and specimens (Table 243). There are 52 samples 

 containing 256 specimens which are unclassified with regard 

 to sediment type. 



Family VENERIDAE 



There are 54 samples in our collection which yielded 117 

 specimens of organisms classified only to the familial level, 

 Veneridae (Table 5). 



Samples yielding members of this family range from Cape 

 Hatteras. N .C. on the continental shelf, south to the environs 

 of Miami, Fla. ( Fig. 1 1 6: Theroux and Wigley footnote 4, table 

 207). 



The range of depth for these samples is 10 to 62 m with a 

 mean of 29 m. The majority of both samples and specimens 

 are in the 25-49 m grouping which contains 57% of the samples 

 and 59% of the specimens, while the 0-24 m grouping contains 

 37% of the samples and 36% of the specimens; the 50-99 m 

 grouping contains 6% of the samples and 5% of the specimens 

 (Table 244). 



Members of the family Veneridae occurred most abundant- 

 ly in sand-shell substrates which yielded 44% of the samples 

 and 47% of the specimens, while sand substrates contained 

 35% of the samples and 35% of the specimens. Other sediment 

 types in which members of this family occurred were gravel, 

 sand-gravel, shell, and silty sand (Table 245). 



Genus Callista Poli 1791 



Callista eucymata (Dall 1890). Glory-of-the-seas venus. Figure 

 21. 



Abbott (1968, 1974) noted that this species is distributed 

 from north Carolina to the southern half of Florida, and from 

 Texas to Brazil, and is uncommon to moderately common 

 within its range. 



There are 14 specimens of this species from 12 samples in 

 the NEFC collection (Table 5). 



Our material ranges from Delaware Bay to southern Flori- 

 da; there are three occurrences north of Cape Hatteras, N.C.: 

 one in Delaware Bay and two at the mouth of Chesapeake 

 Bay; the remaining nine samples are south of Cape Hatteras 

 (Fig. 21; Theroux and Wigley footnote 4, table 34). 



The depth range for this species is from 4 to 214 m (Abbott 

 1968, 1974; Porter 1974). Our samples range from 7 to 74 m in 

 depth with a mean of 21 m. Eighty-three percent of the sam- 

 ples and 79% of the specimens are in the shallowest (0-24 m) 

 depth range grouping; the 25-49 m and 50-99 m groupings each 

 contain 8% of the samples but 7 and 14% of the specimens, 

 respectively (Table 246). 



The glory-of-the-seas venus is usually found in sand sub- 

 strates (Abbott 1968). This observation is true for 58% of our 

 samples and 57% of our specimens. Twenty-five percent of 

 the samples and 29% of the specimens were in sand-shell 

 substrates, while 8 and 7%, respectively, occurred in gravel 

 and silty sand substrates (Table 247). 



Genus Chione Megerle 1811 



Chione intapurpurea (Conrad 1849). Lady-in-waiting venus. 

 Figure 24. 



Chione intapurpurea is reported to occur from North Caro- 

 lina to Florida, the West Indies, Texas, and the Gulf of Mex- 

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

 1973; Emerson et al. 1976). 



The NEFC collection contains eight samples yielding nine 

 specimens of this uncommon species (Table 5). 



Our samples are distributed on the continental shelf from 

 south of Charleston, S.C., to slightly north of Miami, Fla. 

 (Fig. 24; Theroux and Wigley footnote 4, table 38). 



This species is reported to occur in water depths from 2 to 

 86 m (Abbott 1974). 



Our samples are from water depths of from 10 to 28 m with a 

 mean of 17 m. Eighty-eight percent of the samples and 89% of 

 the specimens are in the 0-24 m depth range grouping, while 

 13% of the samples and 11% of the specimens are in the 25-49 

 m depth range grouping (Table 248). 



This species is found on coarse gray sand and under rocks 

 (Abbott 1968); it also occurs on gravelly bottom (Morris 

 1973). 



Our specimens were found in sand-shell and sand sub- 

 strates. These two sediment types each contained 50% of the 

 samples but sand-shell substrates contained 56% of the speci- 

 mens while sand contained 44% (Table 249). 



Chione latilirata (Conrad 1841b). Imperial venus. Figure 25. 



This species occurs from North Carolina to Florida and to 

 Texas; it also occurs in the West Indies and Brazil (Johnson 

 1934; Abbott 1968, 1974; Morris 1973). 



The imperial venus is a rather uncommon offshore species 

 of the U.S. east coast of which there are 24 specimens from 17 

 samples in our collection (Table 5). 



Our samples are located on the continental shelf between 

 Cape Hatteras, N.C., and the central portion of Florida (Fig. 

 25; Theroux and Wigley footnote 4, table 39). 



Depths in which this organism is found range from 18 to 227 

 m (Johnson 1934). 



The depth range of our samples is from 19 to 66 m with a 

 mean of 36 m. The majority of both samples (76%) and speci- 

 mens (83%) are in the 25-49 m depth range grouping. Twelve 

 percent of the samples and 8% of the specimens occur in both 

 the 0-24 m and the 50-99 m depth range groupings (Table 250). 



Our samples were found in sand-shell and sand substrates. 

 Sand contained the majority of samples (71%) and specimens 

 (67%) while the remainder were in sand-shell (Table 251). 



Chione sp. Figure 26. 



There are 58 specimens from 36 samples in our collection 

 which bear the designation Chione sp. (Table 5). 



45 



