I he Paeilu n binges lrom the Aleutian Islands to the Gulf of 

 California (Johnson 1934; La Rocque 1953; Abbott 1968, 

 1974: Morns 1973; Emerson et al. 1976). 



This species, which is often very common in offshore areas, 

 is represented by 352 specimens from 59 samples in our 

 collection (Table 5). 



The NEFC samples range from the continental shelf break 

 south of Nantucket Shoals to the Mid-Atlantic Bight region 

 (Fig. 75; Theroux and Wigley footnote 4, table 127). 



Coomans (1962) placed this species in the Virginian, Caro- 

 linian, and Caribbean provinces, while Gosner (1971) placed 

 it in the Virginian province. 



The depth distribution of this specifies ranges from + 1 to 

 412 m (Johnson 1934; Porter 1974). 



Our samples are from depths ranging between 82 and 366 m 

 with a mean of 149 m. The majority of both samples and 

 specimens are in the 100-199 m depth range grouping which 

 contains 80% of the samples and 90% of the specimens; the 

 50-99 m grouping contains 15% of the samples and 7% of the 

 specimens, while the 200-499 m grouping contains 5% of the 

 samples and 3% of the specimens (Table 22). 



Silty sand substrates contained the majority of both sam- 

 ples and specimens with 42% of the former and 49% of the 

 latter occurring in this sediment type; sand contained 34% of 

 the samples and 38% of the specimens, while clay contained 

 19% of the samples and 11% of the specimens; the least 

 preferred sediment type was silt where 5% of the samples and 

 2% of the specimens occurred (Table 23). 



Nuculana carpenteri (Dall 1881). Carpenter's nut clam. Figure 



75. 



This species ranges from North Carolina to the West Indies 

 (Johnson 1934; Morris 1973; Abbott 1974). 



This is an uncommon bivalve of which the NEFC collection 

 contains 45 specimens from 17 samples (Table 5). 



Our samples are located at the continental shelf break 

 between Cape Hatteras, N.C., and Key West, Fla. (Fig. 75; 

 Theroux and Wigley footnote 4, table 128). 



Although this species prefers deep water (Morris 1973), it 

 ranges between 18 and 525 m depth (Abbott 1974). 



Our samples range in depth between 140 and 400 m of water 

 with a mean of 254 m. The 200-499 m depth range grouping 

 contains the largest amounts of samples (82%) and specimens 

 (89%); the 100-199 m grouping contains 18% of the samples 

 and 11% of the specimens (Table 24). 



Carpenter's nut clam was found in three sediment types 

 within the study area. The majority of samples and specimens 

 occured in silt, yielding 41 and 62%. respectively: silty sand 

 sediments contained 41% of the samples and 22% of the 

 specimens, and sand contained 18% of the samples and 16% 

 of the specimens (Table 25). 



Suculana caudata (Donovan 1801). Tailed nut shell. Figure 75. 



Johnson (1934) and Abbott (1974) reported this species as 

 occurring from the Gulf of Maine to Virginia. 



Nuculana caudata is uncommon in the region: the NEFC 

 collection contains two specimens from one sample (Table 5). 



Our sample is from the western tip of Browns Bank in the 

 Gulf of Maine (Fig. 75; Theroux and Wiglev footnote 4. table 

 129). 



The tailed nut shell is a moderately deep water inhabitant, 

 ranging in depth from 187 to 1,173 m (Johnson 1934: Abbott 

 1974). The NEFC sample is from a water depth of 253 m. This 

 depth range places it in the 200-499 m depth range grouping. 



Our sample was obtained in a substrate of till. 



Nuculana pernula (Miiller 1771). Miiller's nut clam. Figure 76. 



Muller's nut clam is distributed throughout the northern 

 sections of both the Atlantic and Pacific Oceans. In the Atlan- 

 tic it ranges from the Arctic Ocean to Cape Cod, Mass., while 

 in the North Pacific it ranges from northern Alaska to 

 Chatham Sound, British Columbia: it is also found in eastern 

 Siberia (Johnson 1934; La Rocque 1953; Ockelmann 1958; 

 Abbott 1968, 1974; Morris 1973). 



Nuculana pernula is a common bivalve of northern waters: 

 our collection contains 320 specimens from 199 samples 

 (Table 5). 



The NEFC samples are from the Gulf of Maine region with 

 a few straggling samples on the northern part of Georges Bank 

 (Fig. 76: Theroux and Wigley footnote 4. table 130). 



Ockelmann (1958) considered this species to be panarctic- 

 boreal in its distribution, while Gosner (1971) placed it in the 

 Boreal province. 



Muller's nut clam enjoys a rather widespread bathymetric 

 range being found in water depths ranging between 3 and 

 1.643 m (Ockelmann 1958; Porter 1974). 



Our samples are from water depths ranging from 46 to 6 1 1 m 

 with a mean of 145 m. Distribution with increasing depth 

 range is as follows: 3% of the samples and 3% of the speci- 

 mens are in the 25-49 m depth range grouping, 34% of the 

 samples and 51% of the specimens are in the 50-99 m group- 

 ing, 41% of the samples and 32% of the specimens in the 

 100-199 m grouping, 22% of the samples and 14% of the 

 specimens in the 200-499 m grouping, < 1% of both samples 

 and specimens are in the 500-999 m grouping (Table 26). 



This species was found in all of the sediment types consid- 

 ered in this report. Sixteen percent of the samples and 17% of 

 the specimens occurred in gravel, while sand-gravel con- 

 tained 1% of the samples and 0.3% of the specimens: till 

 substrates contained 24% of the samples and 21% of the 

 specimens, while shell contained 2% of both samples and 

 specimens: sand-shell substrates contained 3% of the samples 

 and 2% of the specimens, sand substrates 8% of the former 

 and 5% of the latter, with silty sand containing 14% samples 

 and 26% of the specimens: the two finest grained substrates, 

 silt, contained 8% of the samples and 4% of the specimens, 

 and clay contained 25% of the samples and 25% of the speci- 

 mens (Table 27). There are 6 samples containing 14 specimens 

 which are unclassified with regard to sediment type. 



Nuculana tenuisulcata (Couthouy 1838). Thin nut clam. Figure 



77. 



The thin nut clam is distributed from Arctic seas and the 

 Gulf of St. Lawrence to Rhode Island (Johnson 1934; Morris 

 1951. 1973; La Rocque 1953; Ockelmann 1958; Abbott 1974). 



Nuculana tenuisulcata is the most common Nuculana of 

 New England: it is represented in the NEFC Specimen Refer- 

 ence Collection by 469 specimens from 129 samples (Table 5). 



The NEFC samples are distributed on the continental shelf, 

 from around Nova Scotia, south into the Gulf of Maine (Fig. 

 77: Theroux and Wigley footnote 4. table 131). 



