samples containing 14 specimens had no sediment data in- 

 cluded among recorded environmental parameters. 



Genus Chlamys Bolten 1798 

 Chlamys islandica (Miiller 1776). Iceland scallop. Figure 26. 



This species is reported to occur from Arctic seas to Buz- 

 zards Bay, Mass.. in the North Atlantic, and in the North 

 Pacific ranges from Alaska south to Puget Sound, Wash. 

 (Johnson 1934: La Rocque 1953; Ockelmann 1958: Clark 

 1962: Abbott 1968. 1974; Morris 1973; Emerson etal. 1976). In 

 addition to giving a detailed description of the distribution of 

 this species in Arctic regions. Ockelmann (1958) mentioned 

 that in addition to published distributional records, dead 

 shells have been found from Bohusland in Sweden, in the 

 North Sea, west of Scotland, in Ireland, France, around the 

 Azores, and in the Mediterranean Sea. 



Chlamys islandica is a very common inhabitant of the cold 

 waters of the North Atlantic and North Pacific Oceans. The 

 NEFC collection contains 76 samples which yielded 361 

 specimens of this species (Table 5). 



Our samples are from continental shelf areas north and east 

 of Cape Cod. Mass., on Georges Bank, in the Gulf of Maine, 

 and on the Scotian Shelf west of Nova Scotia (Fig. 26; Ther- 

 oux and Wigley footnote 4, table 41). 



Zoogeographic distribution of this species, according to 

 Ockelmann (1958), is subarctic in both the North Atlantic and 

 North Pacific Oceans: he reported it as continuously cir- 

 cumpolar and found lacking in typically high Arctic seas. 

 Gosner (1971) placed it in the Boreal province in the North 

 Atlantic, while Dance (1974) assigned it to the Arctic, the 

 Boreal east of eastern North America, the Transatlantic, the 

 Aleutian, and Californian provinces. 



Although Chlamys islandica is primarily a continental shelf 

 inhabitant it does range to continental slope depths with re- 

 ported depth records showing it inhabiting water depths 

 which range from 1.8 to 2,031 m (Clarke 1962; Abbott 1968. 

 1974). 



The depth range of our samples is 40 to 42 1 m with a mean of 

 118 m. The majority of samples (53%) are in the 100-199 m 

 depth range grouping. 38% in the 50-99 m grouping, 5% in the 

 200-400 m depth range grouping, and 4% in the 25-49 m 

 grouping: whereas, the specimen distribution is 75% of the 

 specimens in the 50-99 m grouping, 22% in the 100-199 m 

 grouping. 2% in the 200-499 m grouping and < 1% in the 25-49 

 m grouping (Table 110). 



Abbott (1968) reported that the Iceland scallop occurs on 

 coarse sand sediments. 



Our samples occurred in all but two of the nine sediment 

 types included in this report. No specimens were obtained 

 from shell or sand-shell substrates. Largest amounts of both 

 samples and specimens occurred in the coarser grained sub- 

 strate types, gravel, sand-gravel, till, and sand with signifi- 

 cantly lesser amounts of each occurring in the finer grained 

 sediments, silty sand, silt, and clay (Table 111). There are 28 

 samples containing 85 specimens which are unclassified with 

 regard to sediment type. 



Genus Cyclopecten Verrill 1897 



Cyclopecten nanus Verrill and Bush 1897. Dwarf round scallop. 

 Figure 40. 



The dwarf round scallop occurs from off Virginia to Texas, 

 and at Puerto Rico and Brazil (Johnson 1934: Warmke and 

 Abbott 1961; Morris 1973; Abbott 1974). 



The NEFC collection contains 21 specimens of this species 

 from 3 samples (Table 5). 



Our samples are located on the edge of the Continental shelf 

 off Atlantic City, N.J. (Fig. 40; Theroux and Wigley footnote 

 4, table 64). 



The depth range for this tiny species is 40 to 538 m (Abbott 

 1974). 



Samples in our collection range from 89 to 102 m depth with 

 a mean of 93 m. Two depth range groupings contain members 

 of this species, the 50-99 m grouping with 67% of the samples 

 and 52% of the specimens and the 100-199 m grouping con- 

 taining 33% of the samples and 48% of the specimens (Table 

 112). 



All of our samples were obtained in sand substrates (Table 

 113). 



Cyclopecten pustulosus Verrill 1873a. Figure 40. 



Cyclopecten pustulosus ranges from Newfoundland to 

 Cape Cod and Martha's Vineyard, Mass. (Johnson 1934: La 

 Rocque 1953: Ockelmann 1958; Abbott 1974). 



The NEFC Specimen Reference Collection contains 58 

 specimens from 30 samples of Cyclopecten pustulosus (Table 

 5). 



Our samples are from north and east of Cape Cod. Mass.. 

 the Gulf of Maine, the Scotian Shelf, and on the outer con- 

 tinental slope south of Georges Bank (Fig. 40: Theroux and 

 Wigley footnote 4. table 65). 



The bathymetric range of this species is 21 1 to 787 m of 

 water (Johnson 1934; Abbott 1974). 



The range in depth of our samples is from 1 10 to 690 m with 

 a mean of 218 m. Three depth range groupings are incuded in 

 this bathymetric range with abundance decreasing with in- 

 creasing depth range. The 100-199 m depth range grouping 

 contains 63% of the samples and 54% of the specimens, while 

 the 200-499 m grouping contains 30 and 43%. respectively: the 

 500-999 m grouping contains 1% of the samples and 3% of the 

 specimens (Table 114). 



There is no great disparity of abundance among the se\ era] 

 sediment types in which this species was found. Twenty-four 

 percent of the samples occurred in both sand-gravel and sand 

 substrates which contained 16 and 14% of the specimens, 

 respectively: 20% of the samples occurred in both till and silty 

 sand where 32 and 14% of the specimens occurred, respec- 

 tively ; gravel substrates contained 8% of the samples and 23% 

 of the specimens, while clay contained the least with 4% of the 

 samples and 2% of the specimens (Table 115). There are 5 

 samples containing 14 specimens which are unclassified with 

 regard to sediment type. 



21 



