Cuspidaria obesa (Loven 1846). Obese dipper shell. Figure 35. 



The distribution of this species ranges from the Arctic 

 Ocean to the West Indies in the northwest Atlantic (Johnson 

 1934; La Rocque 1953; Abbott 1974). Ockelmann (1958) and 

 Clarke (1962) have compiled extensive lists of its distribution 

 throughout Arctic regions as well as the European side of the 

 North Atlantic showing it to range from Norway, western 

 Europe, and the Canary Islands, south into the Mediterra- 

 nean Basin. 



This species is represented in the NEFC collection by 14 

 samples containing 30 specimens (Table 5). 



Our samples are from the Gulf of Maine Basin and slope 

 waters from Georges Bank to the offing of Delaware Bay (Fig. 

 35; Theroux and Wigley footnote 4, table 55). 



This species is subarctic-boreal, Mediterranean- Atlantic, 

 and abyssal (Ockelmann 1958). 



This species inhabits water depths between 18 and 4,456 m 

 (Clarke 1962). 



Our samples are from depths ranging between 1 14 and 720 

 m with a mean of 401 m. The 200-499 m and the 500-999 m 

 depth range groupings each contain 36% of the samples, but 

 the former contains 23% and the latter 40% of the specimens. 

 The other range grouping in which this species occurs is the 

 100-199 m grouping containing 29% of the samples and 37% of 

 the specimens (Table 316). 



Our samples were obtained from a variety of sediment 

 types which included gravel, till, sand, silty sand, silt, and 

 clay. The largest amount of samples (29%) were in silty sand; 

 this substrate also contained the greatest number of speci- 

 mens (37%). Other sediment types contained 7 to 21% of the 

 samples and from 6 to 17% of the specimens (Table 317). 



Cuspidaria parva Verrill and Bush 1898. Figure 35. 



This species occurs off Cape Cod, Mass., in the North 

 American Basin (Johnson 1934; Clarke 1962; Abbott 1974). 

 The locations of our two samples are: 1) off the coast of Maine 

 in the Gulf of Maine, and 2) on the continental slope between 

 New York and Atlantic City, N.J. (Fig. 35; Theroux and 

 Wigley footnote 4, table 56). 



The reported depth range for this species is 90 to 2,361 m 

 (Abbott 1974; Porter 1974). 



There are three specimens from two samples of this rather 

 rare bivalve species in the NEFC collection (Table 5). 



The two samples in the NEFC collection are from 95 and 

 1,328 m of water. The shallower sample is in the 100-199 m 

 depth range grouping and contains one specimen while the 

 deep one is located in the 500-999 m depth range grouping and 

 contains two specimens (Table 318). 



One sample occurred in silt sediments and contained two 

 specimens while the second sample was obtained from clay 

 substrates and contained one specimen (Table 319). 



Cuspidaria pellucida Stimpson 1853. Figure 36. 



The geographic distribution of this species ranges from the 

 Gulf of St. Lawrence to Casco Bay, Maine (Johnson 1934; La 

 Rocque 1953; Abbott 1974); Ockelmann (1958) reported it to 

 occur from Newfoundland to Cape Cod, Mass. 



This rather rare species is represented in the NEFC collec- 

 tion by 19 specimens from 4 samples (Table 5). 



Our samples are from off the coast of Maine on the con- 

 tinental shelf and from the Gulf of Maine Basin proper (Fig. 

 36; Theroux and Wigley footnote 4, table 57). 



The bathymetric range of this species is from 73 to 174 m 

 (Abbott 1974). 



Our samples range in depth from 75 to 178 m with a mean of 

 123 m. Seventy-five percent of the samples and 74% of the 

 specimens are in the 100-199 m depth range grouping and 25% 

 of the samples and 26% of the specimens are in the 50-99 m 

 depth range grouping (Table 320). 



Sixty-seven percent of the samples and 36% of the speci- 

 mens occurred in silty sand substrates (Table 321). One sam- 

 ple containing five specimens is unclassified with regard to 

 sediment type. 



Cuspidaria rostrata (Spengler 1793). Rostrate cuspidaria. Fig- 

 ure 36. 



This species is reported to occur from Arctic seas to the 

 West Indies in the North Atlantic and is also found in Europe 

 (Johnson 1934; La Rocque 1953; Morris 1973; Abbott 1974). 

 Ockelmann (1958), Clarke (1962), and Tebble (1966) have 

 complete lists of its Arctic and subarctic distribution as well 

 as its European distribution. Tebble mentioned that it is also 

 present in the Mediterranean, along the Atlantic coast of 

 Morocco, in the Canary Islands, the Azores, and Sierra 

 Leone and Liberia on the African coast. 



This is a moderately common bivalve of which there are 

 two samples containing nine specimens in the NEFC Speci- 

 men Reference Collection (Table 5). 



Our samples are from the edge of the continental shelf south 

 of Georges Bank (Fig. 36; Theroux and Wigley footnote 4, 

 table 58). 



The rostrate cuspidaria is a deep water species which 

 ranges from 64 to 2,999 m in depth (Johnson 1934; Clarke 

 1962). 



The NEFC samples are from depths ranging from 121 to 144 

 m with a mean of 1 33 m. This depth range places both samples 

 in the 100-199 m depth range grouping. 



The two samples which yielded specimens of the rostrate 

 cuspidaria were obtained in a sand substrate. 



Cuspidaria sp. Figure 37. 



There are 1 14 specimens from 69 samples which are identi- 

 fied to the generic level Cuspidaria in the NEFC collection 

 (Table 5). 



The 69 samples containing members of the genus Cuspidar- 

 ia are distributed in two groupings within the study area. The 

 first group ranges from the Gulf of Maine Basin south to the 

 outer banks of Cape Cod, Mass.: the second is a more deeply 

 distributed group of samples on the continental shelf and 

 slope , ranging from the middle part of southern Georges Bank 

 to the offing of Chesapeake Bay (Fig. 37; Theroux and Wigley 

 footnote 4, table 59). 



Our samples are from water depths which range from 44 to 

 2,035 m with a mean of 331 m. The majority of samples are in 

 the 100-199 m depth range grouping which contains 49% of the 

 samples and 55% of the specimens. Next largest amounts are 

 in the 200-499 m depth range grouping accounting for 39 and 

 30% for samples and specimens, respectively: significantly 

 lower amounts of both samples and specimens occur in the 

 other depth range groupings (Table 322). 



57 



