Fundy also provided specimens (Fig. 1 1 ; Theroux and Wigley 

 footnote 4, table 17). 



The zoogeographic distribution of this species is Boreal and 

 Virginian (Coomans 1962; Gosner 1971), but Dance (1974) 

 assigned it to the Boreal and Transatlantic provinces. 



Depths occupied by A. castanea range from 9 to 152 m 

 (Johnson 1934; Abbott 1968). 



This common species is well represented in the NEFC 

 collection which contains 458 specimens from 106 samples 

 (Table 5). 



Our samples are from depths between and 123 m with a 

 mean of 46 m. Samples and specimens are fairly evenly distri- 

 buted among three of our depth range groupings (0-24, 25-49, 

 and 50-99 m) which collectively account for nearly 96% of the 

 samples and 99% of the specimens, the balance is in the 

 100-199 m grouping (Table 178). One sample with one speci- 

 men had no information relating to depth. 



Samples containing the smooth astarte were absent in till 

 and silt sediments. The majority of samples (65%) and speci- 

 mens (63%) occurred in sand; sand-gravel yielded 14% of the 

 samples and 24% of the specimens; other sediments in which 

 they occurred (gravel, shell, sand-shell, silty sand, and silt) 

 each contained significantly smaller quantites of both samples 

 and specimens (Table 179). There are 12 samples containing 

 74 specimens which are unclassified with regard to sediment 

 type. 



Astarte crenata subequilatera Sowerby 1854. Lentil astarte. Fig- 

 ure 12. 



This species is reported to occur from Arctic seas including 

 Labrador and the Gulf of St. Lawrence to Florida (Johnson 

 1934;Morris 1951, 1973; LaRocque 1953; Abbott 1968, 1974). 

 It is widely distributed in the Arctic and is considered by 

 Ockelmann (1958), along with its subspecies, to be panarctic 

 and circumpolar. 



The lentil astarte is a common bivalve which occurs in 4% 

 of our samples representing nearly 5% of the total number of 

 specimens (Table 5). These values make it the fourth most 

 plentiful in terms of samples and fifth ranked in terms of 

 specimens. 



Our samples are concentrated, for the most part, in the 

 more northerly regions of our study area. The majority of 

 samples are in the Gulf of Maine and around the periphery of 

 Georges Bank; others, in diminishing numbers, occupy the 

 continental shelf, slope, and rise in the region of southern 

 New England and off the Middle Atlantic Bight south to off 

 Maryland; no samples occur between Maryland and south of 

 Cape Hatteras, N.C., but reappear on the outer shelf and 

 upper slope between South Carolina and Jacksonville, Fla.; 

 two samples contaning specimens occur off the Florida Keys 

 (Fig. 12; Theroux and Wigley footnote 4. table 18). 



The zoogeographic distribution is Arctic, Boreal, Virginian, 

 and Carolinian (Coomans 1962); Gosner (1971) considered it 

 Boreal and Virginian. 



The reported depth range of the lentil astarte is 24 to 783 m 

 (Morris 1973: Abbott 1974). This species occurs in shallow 

 water in the northern reaches of its range, but in the southern 

 sectors is found only below 92 m (Abbott 1974). Ockelmann's 

 (1958) reported depth range for Arctic regions is from 4 m at 

 Spitzbergen down to 1,275 m near Jan Mayen. 



Our samples range from 23 to 61 1 m in depth with a mean of 

 150 m. The majority of both samples and specimens are in the 

 mid to deep (shelf break) continental shelf depth range group- 

 ings and in the upper slope grouping (50-99, 100-199, and 

 200-499 m); fewer samples occur in both shallower and deeper 

 depth range groupings (Table 180). 



Moderate amounts of samples occurred in a variety of 

 sediment types: till (22%), sand (18%). silty sand (17%), 

 gravel (14%), clay (13%), and sand-gravel (1 1%); significantly- 

 lower amounts occurred in silt (3%). shell (2%), sand-shell 

 (0.5%). There is a wider disparity among sediment types with 

 regard to number of specimens; 49% of the specimens were in 

 till substrates, 15, 14. and 13% in gravel, sand, and silty sand. 

 respectively, with other sediments containing between 5 and 

 0.5% (Table 181). There are 42 samples containing 323 speci- 

 mens which are unclassified with regard to sediment type. 



Astarte elliptica (Brown 1827). Elliptical astarte. Figure 13. 



This species occurs from Arctic seas near Greenland to 

 Massachusetts and also in Europe (Johnson 1934: La Rocque 

 1953; Abbott 1974). Ockelmann's (1958) distributional data 

 show it occupying most Arctic regions including Denmark 

 and Great Britain, it also occurs in the west Baltic to Born- 

 holm and in France; he considers it panarctic-boreal only in 

 the North Atlantic. 



The elliptical astarte, which is a moderately common 

 bivalve, is represented in our collection by 317 specimens 

 from 42 samples (Table 5). 



Our samples are from the periphery of the Gulf of Maine, on 

 the Northeast Peak and Southwest Part of Georges Bank, 

 some are in Cape Cod Bay and a few on the Middle Atlantic 

 Bight continental shelf (Fig. 1 3 ; Theroux and Wigley footnote 

 4, table 19). 



The reported depth range for this species is 15 to 165 m 

 (Johnson 1934; La Rocque 1953; Abbott 1974); Ockelmann 

 (1958) reported it from 2 m at East Greenland to 442 m at West 

 Greenland. He further stated that dead shells of this species 

 have been found in the North Atlantic down to 2,465 m. 



Our samples range in depth from 23 to 156 m with a mean of 

 77 m. The majority of samples (76%) and specimens (83%) are 

 in the 50-99 m depth range grouping with lesser amounts in the 

 0-24, 25-49, and 100-199 m groupings (Table 182). 



The relation of this species to bottom sediments contains 

 some disparities depending upon which measure is being 

 considered , 1 ) number of samples or, 2) number of specimens , 

 occurring in each sediment type. To avoid possible misunder- 

 standing each sediment type will be taken in turn, see Table 

 183. Gravel contained 13% of the samples and 18% of the 

 specimens; sand-gravel contained the highest proportion of 

 samples (23%), but only yielded 4% of the specimens; till had 

 a fairly even ratio, 19% of the samples and 21% of the spe- 

 cimens; shell with only 10% of the samples yielded the 

 greatest number of specimens (41%) of any bottom type; only 

 3% of the samples and 0.3% of the specimens occurred in 

 sand-shell; 19% of the samples and 4% of the specimens 

 occurred in sand; silty sand contained 3% of the samples and 

 3.5% of the specimens; none occurred in silt, but clay con- 

 tained 10% of the samples and 9% of the specimens. There are 

 11 samples with 33 specimens which are unclassified with 

 regard to sediment type. 



33 



