occurred in gravel; 16 and 44%, respectively, in sand-gravel; 3 

 and 1%, respectively, in till; 2 and 0.3%, respectively, in shell, 

 with an increase in sand to 44% for samples and 13% for 

 specimens; silty sand contained 23% of the samples and 38% 

 of the specimens, silt 2% for samples and 0.1% of the speci- 

 mens, while clay contained 5% of the samples and 1% of the 

 specimens (Table 1 07) . There are 45 samples containing 4 , 1 89 

 specimens which are unclassified with regard to sediment 

 type. 



Order PTERIOIDA 

 Family PECTINIDAE 



The NEFC collection contains 14 samples yielding 23 

 specimens which are classified to the family level Pectinidae 

 (Table 5). 



Samples containing members of this taxon are distributed 

 throughout the study area in isolated patches from Nova 

 Scotia south to north of Miami, Fla. (Fig. 84: Theroux and 

 Wigley footnote 4, table 145). 



Members of the family Pectinidae in the NEFC collection 

 range in depth between 23 and 310 m with a mean of 104 m. 

 Table 108 lists the occurrence of members of the Pectinidae in 

 relation to range in water depth. 



Sediment types in which members of this family were found 

 included gravel, shell, sand-shell, sand, silty sand, and silt. 

 Table 109 lists the occurrence of Pectinidae in our collection 

 in relation to bottom sediments. There are two samples con- 

 taining two specimens which are unclassified with regard to 

 sediment type. 



Genus Aequipecten Fischer 1886 



Aequipecten phrygium (Dall 1886). Spathate scallop. Figure 3. 



This scallop is distributed from Cape Cod. Mass.. to Flor- 

 ida and the West Indies (Johnson 1934; Abbott 1974: Porter 

 1974). Abbott (1974) considered it uncommon off Miami and 

 the lower Florida Keys. 



The spathate scallop is represented by 10 specimens from 1 

 sample in the NEFC collection (Table 5). 



Our sample is from the outer continental shelf southeast of 

 the eastern tip of Long Island, N.Y. (Fig. 3; Theroux and 

 Wigley footnote 4, table 4). 



The main distribution is Boreal. Virginian, and Carolinian 

 in American waters (Coomans 1962). 



The spathate scallop is a moderately deep water inhabitant 

 occupying depths which range from 92 to 1.449 m (Johnson 

 1934: Morris 1951). 



Our sample is from a depth of 93 m in a clay bottom. 



Genus Argopecten Monterosato 1889 

 Argopecten gibbus (Linne 1758). Calico scallop. Figure 9. 



The calico scallop occurs from off Maryland to Florida, in 

 the Gulf of Mexico, and at south Texas (Johnson 1934: Morris 

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



Although Argopecten gibbus is a common, warm water, 

 commercially important bivalve our collection contains only 

 two specimens from two samples (Table 5) due to the lack of 

 sampling activity by NEFC in its distributional range in com- 

 parison to that in more northerly areas. 



Our samples are from the northern Florida continental shelf 

 (Fig. 9; Theroux and Wigley footnote 4, table 14). 



Published depth data for this species shows a distribution 

 ranging from shallow water to 366 m (Abbott 1968. 1974: 

 Morris 1973). 



Our samples are from 28 and 35 m with a mean depth of 32 

 m. All samples and specimens are in the 25-49 m depth range 

 grouping. 



The samples are from sand substrates. 



Argopecten irradians (Lamarck 1819). Atlantic bay scallop. 

 Figure 9. 



The Atlantic bay scallop is an abundant, commercially 

 important bivalve of the U.S. east coast, especially in the 

 northeastern region, although elsewhere along the coast, 

 where locally abundant, important fisheries also exist (Gut- 

 sell 1931; Marshall 1960; Clarke 1964). 



Clarke (1964), in his review of the taxonomy of the genus 

 Aequipecten, agreed with Abbott's (1954) differentiation of 

 the A. irradians superspecies into three subspecies: A. irra- 

 dians s.s., A. i. concentricus (Say), and A. i. amplicostatus 

 (Dall), and added a new subspecies, A. i. sablensis, which 

 occurs only at Cape Sable, Nova Scotia, to the list. Our 

 specimens are A. irradians s.s.. 



Most published distributional records are for the so-called 

 superspecies A. irradians which ranges from Newfoundland 

 to Florida and Texas (Johnson 1934; La Rocque 1953; Ockel- 

 mann 1958; Abbott 1968, 1974; Morris 1973; Emerson et al. 

 1976). Gutsell (1931) listed the occurrence of this organism, in 

 important commercial abundance, to range from Cape Cod to 

 Bogue Sound. N.C., but cited other authors, namely Dall 

 (1889, 1898), Belding (1910), Kellogg (1910), and Ingersoll 

 ( 1 887) who considered it distributed from Maine to Texas , the 

 West Indies, and Brazil. Clarke (1964) considered the super- 

 species A. i. irradians to inhabit the region from the north 

 shore of Cape Cod at Barnstable and Provincetown, Mass., to 

 New Jersey with disjunct populations at Cohasset and Scitu- 

 ate, Mass. 



Due to the restriction of this species to inshore habitats and 

 the relatively few samples from these areas in our collection, 

 we have only 5 samples containing 17 specimens of this ani- 

 mal (Table 5). 



Our samples are all from the south shore of Cape Cod and 

 adjacent Vineyard Sound (Fig. 9; Theroux and Wigley foot- 

 note 4, table 15). 



The zoogeographic distribution of this species complex is 

 Boreal, Virginian, and Carolinian in the western Atlantic, and 

 Celtic for the genus in Europe (Coomans 1 962) ; Gosner ( 197 1 ) 

 considered it Boreal and Virginian, while Dance (1974) placed 

 it in the Transatlantic and Caribbean provinces. 



The depth range of this species is relatively narrow restrict- 

 ing it to inshore embayments and sounds. Reported depths 

 range from 0.3 to 18 m (Gutsell 1931; Abbott 1974). 



Our samples range from to 3 m with a mean of 1.2 m, 

 placing them in our 0-24 m depth range grouping. 



Argopecten irradians has a close affinity to eelgrass (Zos- 

 tera) beds and other vegetation areas on bottom types com- 

 posed of soft mud to hard, non-shifting sand (Gutsell 1931; 

 Marshall 1960; Clarke 1964; Abbott 1974). 



Thirty-three percent of our samples and specimens came 

 from a sand-gravel bottom, 67% of each were in sand, while 2 



20 



