Bathyarca pectunculoid.es (Scacchi 1834). Scalloplike ark. Fig- 

 ure 19. 



Bathyarca pectunculoides occurs from the Gulf of St. 

 Lawrence to off Cape Cod, Mass. , and is also found in Green- 

 land (Johnson 1934; La Rocque 1953; Morris 1973; Abbott 

 1974). Ockelmann (1958) showed a fairly widespread distribu- 

 tion in Arctic regions and the North Sea, while Clarke's ( 1962) 

 data extended its distribution to include the Gulf of Mexico, 

 North Eurasia, Western Europe, the Canaries, and the 

 Mediterranean Sea. 



There are 1,297 specimens from 157 samples of this species 

 in our collection (Table 5). 



Our samples, in the main, are from the Gulf of Maine and 

 around Nova Scotia with a few occurring on the mid to upper 

 continental slope from southern Georges Bank south to off 

 Atlantic City, N.J. (Fig. 19: Theroux and Wigley footnote 4, 

 table 30). 



Gosner (1971) placed this species in the Boreal province. 



The scalloplike ark is a deep water inhabitant, occupying a 

 depth range of from 49 to 926 m (Johnson 1934); Clarke (1962) 

 listed a depth range of 37 to 3,312 m. 



Our samples range from 73 to 458 m in depth with a mean of 

 184 m. The majority of our samples (61%) and specimens 

 (73%) are in the 100-199 m depth range grouping: the 200-499 

 m grouping contains 34% of the samples and 20% of the 

 specimens, while the 50-99 m grouping contains only 5 and 7% 

 of the samples and specimens, respectively (Table 64). 



Sand and sand-shell were the only two sediment types 

 which did not contain members of this species. The largest 

 number of samples were in silty sand (36%), with till, gravel, 

 and clay containing diminishing but significant amounts (20, 

 16. and 10%. respectively). Sand-gravel, sand, and silt sedi- 

 ments each contained < 8% of the samples. Gravel yielded 

 the greatest amount of specimens (44%), followed by till 

 (32%) and silty sand (14%). Sand-gravel, sand, silt, and clay 

 each accounted for < 4% of the specimens (Table 65). There 

 are 17 samples containing 202 specimens which are unclassi- 

 fied with regard to sediment type. 



Bathyarca sp. Figure 20. 



The NEFC collection contains 14 specimens of Bathyarca 

 sp. from 9 samples (Table 5). 



Samples yielding spcimens of Bathyarca sp. are from the 

 Gulf of Maine (Fig. 20: Theroux and Wigley footnote 4. table 

 31). 



The depth range of our samples is 128 to 242 m with a mean 

 of 182 m. Two-thirds of the samples and 79% of the specimens 

 are in the 100-199 m depth range grouping, and 33% of the 

 samples with 21% of the specimens are in the 200-499 m 

 grouping (Table 66). 



No members of this taxon were found in gravel, sand-shell, 

 or silt substrates. One-third of the samples containing 50% of 

 the specimens occurred in clay sediments; 1 1 to 22% of the 

 samples and 7 to 14% of the specimens occurred in other 

 sediment types (Table 67). 



Genus Noetia Grey 1840 

 Noetia ponderosa (Say 1822). Ponderous ark. Figure 70. 



The distribution of this species is from Cape Cod to Florida 

 and Texas and it also occurs in the West Indies. It is uncom- 

 mon in the northern reaches of the study area but very abun- 

 dant south of Cape Hatteras, N.C. (Johnson 1934; Morris 

 1951, 1973; Abbott 1968, 1974; Emerson et al. 1976). 



Noetia ponderosa is very common and abundant in south- 

 ern regions; there are only five specimens of this species from 

 one sample in our collection (Table 5). 



Our sample is from inshore Connecticut waters (Fig. 70; 

 Theroux and Wigley footnote 4, table 122). 



The zoogeographic distribution of this species is in the 

 Virginian and Carolinian provinces for American waters 

 (Coomans 1962); Gosner (1971) placed it in the Virginian 

 province, while Dance (1974) placed it in the Transatlantic 

 and Caribbean provinces. 



The ponderous ark is primarily a shallow water inhabitant 

 but does range out to 37 m in depth (Abbott 1968, 1974; Porter 

 1974). 



Our sample is from a water depth of 1 m. This depth places 

 it in the 0-24 m depth range grouping. 



Abbott (1958, 1974) and Morris (1973) reported the ponder- 

 ous ark from sand bottoms. The NEFC sample is unclassified 

 with regard to sediment type. 



Family LIMOPSIDAE 



There are 16 samples containing 1 ,052 specimens which are 

 identified to the level of family Limopsidae in our collection 

 (Table 5). 



Samples containing members of this taxon are distributed 

 from slightly south and offshore of Delaware Bay and at the 

 entrance to Chesapeake Bay and range, with a gap at Cape 

 Hatteras, N.C, to Key West, Fla. (Fig. 52; Theroux and 

 Wigley footnote 4, table 85). 



Our samples of this taxon range in depth from 13 to 60 m 

 with a mean of 259 m. Fifty percent of the samples and 3% of 

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

 25% of the samples but 97% of the specimens are in the 

 200-499 m grouping; the 500-999 m grouping contains 13% of 

 the samples but only 0.3% of the specimens; the 0-24 m 

 grouping and the 50-99 m grouping each contain 6% of the 

 samples but 0.2 and 0.1% of the specimens, respectively 

 (Table 68). 



The majority of samples and specimens were obtained in 

 sand which contained 50% of the samples and 99% of the 

 specimens; gravel contained 6% of the samples and 0.2% of 

 the specimens, sand-shell 19% of the samples and 0.5% of the 

 specimens, while silty sand and silt each contained 13% of the 

 samples and 0.3 and 0.2% of the specimens, respectively 

 (Table 69). 



Genus Limopsis Sassi 1827 



Limopsis affinis Verrill 1885. Gregarious limopsis. Figure 52. 



Both Johnson (1934) and Abbott (1974) reported this spe- 

 cies as occurring south of Martha's Vineyard, Mass., where- 

 as, Morris (1973) reported it as occurring from Massachusetts 

 to Florida. 



13 



