Although Petricola pholadiformis is very common, the 

 NEFC collection contains only 27 specimens from 7 samples 

 of this species (Table 5). 



The samples in the NEFC collection are from two locali- 

 ties; the majority of samples are in the Cape Cod region, 

 especially in Buzzards Bay, and one sample is from just north 

 of Jacksonville, Fla. (Fig. 88: Theroux and Wigley footnote 4. 

 table 152). 



The real or main distribution of this species is in the Boreal, 

 Virginian, and Carolinian provinces in the northwest Atlantic 

 and Celtic in the eastern Atlantic (Coomans 1962); Gosner 

 (1971) placed it in the Boreal and Virginian provinces, while 

 Dance (1974) considered it to occupy the Boreal. Mediterra- 

 nean, West African, Transatlantic, Caribbean, and Califor- 

 nian provinces. 



This species is primarily intertidal; however, it does range 

 down to approximately 13 m depth (Morris 1951, 1973: Porter 

 1974). 



The range of depth for the NEFC samples is 1 to 26 m with a 

 mean of 7 m. The majority of both samples and specimens are 

 in the shallowest depth range grouping, the 0-24 m, where 

 86% of the samples and 96% of the specimens are grouped : the 

 25-49 m grouping contains 14% of the samples and 4% of the 

 specimens (Table 262). 



The most common habitat for the false angel wing is in stiff 

 clays, peats, and in mud banks since it is a borer (Morris 195 1 , 

 1973; Abbott 1968, 1974). 



There was only a small amount of sediment information 

 accompanying the NEFC samples. Three samples contained 

 sediment data: one from shell, one in sand, and one in silty 

 sand. Table 263 lists the distribution of samples and speci- 

 mens with regard to sediment type. There are 4 samples 

 containing 21 specimens which are unclassified with regard to 

 sediment type. 



Order MYOIDA 

 Family MYIDAE 



Genus Mya Linne 1758 

 Mya arenaria Linne 1758. Soft-shell clam. Figure 68. 



Mya arenaria is a commercially valuable bivalve of the 

 northeast United States which, in 1978, yielded 10.1 million 

 pounds of meats (Pileggi and Thompson 1979). Its commercial 

 importance has resulted in a multitude of common names by 

 which this bivalve is known, among them are the following: 

 soft-shell clam, steamer clam, long clam, soft clam, sand 

 gaper, long neck clam, nannynose, mannynose, and soft- 

 shelled clam. 



The normal distribution of the soft-shell clam is from Lab- 

 rador to South Carolina, extending, locally, south to Florida; 

 it is also distributed throughout western Europe and has been 

 introduced to western U.S. waters at Alaska and Monterey, 

 Calif.; there are also small isolated populations in Arctic 

 regions (Johnson 1934; Foster 1946; Morris 1951, 1973; La 

 Rocque 1953; Ockelmann 1958; Tebble 1966; Abbott 1968. 

 1974; Emerson et al. 1976). 



There are 290 specimens of this bivalve from 64 samples in 

 the NEFC collection (Table 5). 



Our samples are from the northeastern sector of the study 

 area from the inshore waters of Maine, New Hampshire, 



Massachusetts, south to New York State, and New Jersey; 

 there is one isolated community at Charleston, S.C. (Fig. 68; 

 Theroux and Wigley footnote 4, table 116). 



Coomans (1962) placed the distribution of Mya arenaria in 

 the Arctic, Boreal, and Virginian zoogeographic provinces in 

 the western Atlantic, and the Celtic province in Europe: 

 Gosner ( 1 97 1 ) placed it in the Boreal and Virginian provinces ; 

 Dance (1974) considered it to occupy the Boreal, Transatlan- 

 tic, Aleutian, Californian, and Japonic provinces. 



Mya arenaria is primarily an intertidal organism; however, 

 it does on occasion, in certain areas, reach subtidal depths, 3 

 to 9 m, and perhaps deeper (Abbott 1968; Gosner 1971). 



The depth range of our samples is from to 192 m with a 

 mean depth of 43 m. The majority of samples (44%) and 

 specimens (50%) are in the 0-24 m depth range grouping; 32% 

 of the samples and 34% of the specimens are in the 50-99 m 

 grouping; 16% of the samples and 10% of the specimens are in 

 the 25-49 m grouping, and 8% of the samples and 6% of the 

 specimens in the 100-199 m grouping (Table 264). There are 

 two samples containing nine specimens for which no depth 

 information is available. 



Of the nine sediment types considered in this report, Mya 

 arenaria was absent from only one, sand-shell. The majority 

 of samples and specimens occurred in silty sand substrates 

 which contained 38% of the samples and 42% of the spe- 

 cimens ; next highest amount occurred in clay with 2 1 % of the 

 samples and 20% of the specimens. Both sand and silt con- 

 tained 13% of the samples, but 5 and 29% of the specimens, 

 respectively. Smaller amounts occurred in gravel, sand- 

 gravel, till, and shell substrates (Table 265). Eleven samples 

 containing 28 specimens are unclassified with regard to sedi- 

 ment type. 



Family CORBULIDAE 



Our collection contains 150 specimens from 56 samples 

 which for various reasons were identified to the family level 

 Corbulidae (Table 5). 



The samples containing members of this taxon are distri- 

 buted on the continental shelf between Cape Hatteras, N.C., 

 and Miami, Fla. (Fig. 29; Theroux and Wigley footnote 4, 

 table 46). 



The samples containing members of the Corbulidae range 

 in depth from 5 to 128 m with a mean of 30 m. Fifty-nine 

 percent of the samples and 56% of the specimens are in the 

 0-24 m range grouping: 21 and 25%, respectively, in the 25-49 

 m grouping; 18% of both samples and specimens are in the 

 50-99 m range grouping, and 2% of the samples and 1% of the 

 specimens are in the 100-199 m grouping (Table 266). 



Members of this taxon preferred sandy substrates over 

 coarser or finer sediments. Forty-one percent of the samples 

 and 38% of the specimens occurred in sand; 38% of the 

 samples and 38% of the specimens occurred in sand-shell, and 

 14 and 19%. respectively, occurred in silty sand. The other 

 two sediment types which contained members of this taxon 

 were shell with 5% of the samples and 4% of the specimens 

 and gravel with 2 and 1%. respectively (Table 267). 



Genus Corbula Brugiere (1792) 



Corbula contracta Say 1822. Contracted corbula. Figure 27. 



The contracted corbula is reported to occur from Cape Cod 



48 



