curring between 30 and 49 m (Table 12). The highest 

 mean density (400/01^) occurred between 20 and 29 m. 

 This species occurred much less frequently in shallow 

 water in the southern pwrtion of our study area. Only one 

 of the 33 stations south of Sandy Hook was in <30 m, 

 whereas 12 of the 50 stations north of Sandy Hook were 

 in <30 m. This trend indicates that C. crassicome has a 

 tendency for southern submergence. 



Table 12. — Bathymetric distribution of Corophium 

 cmtiicome in samples from .Middle .Atlantic Bight. 



Sediment Relationship. Bousfield (1973) stated that C. 

 crassicorne is usually found on consolidated sandy bot- 

 toms. In our collections, this species occurred on sedi- 

 ments ranging from gravel to silty sand, but it was most 

 common (79/96) on sand bottoms (Table 13). 



Table 13. — Sediment associations of Corophium cra»- 

 ticome in samples from Middle Atlantic Bight. 



Corophium tuberculatum Shoemaker 1934 



This tube-dwelling amphipod has been reported from 

 bays and estuaries between the Bay of Fundy and the 

 Gulf of Mexico (Bousfield 1973). In our collections, C. 

 tuberculatum occurred at seven stations in coastal and 

 protected waters from Nantucket, Mass., to Chesa- 

 peake Bay (Fig. 7). All of these stations were in shallow 

 water (8-16 m), but a wide variety of sediment types was 

 represented including gravelly shell, shell, sand, sand- 

 silt-clay, shelly silt-clay, and clayey silt. This species 

 was moderately abundant with a mean density of 50/m^, 

 ranging between 10/m^ and 150/m^. 



Gammaropaia maculatuB (Johnston) 1827 



According to Bousfield (1973), this species is amphi- 

 Atlantic in the boreal regions, and it is known to occur 

 south to North Carolina in the northwestern Atlantic 

 (Fox and Bynum 1975). Gammaropsis maculatus oc- 

 curred at a single station off Norfolk, Va., in our collec- 

 tions (Fig. 7), at 22 m on a gravelly sand bottom. 



Gammaropsis nitida (Stimpson) 1853 



This species is amphi-Altantic in the boreal regions, 

 being found from the Gulf of St. Lawrence south to Con- 

 necticut along the east coast of North America (Bous- 

 field 1973). It occurred in low densities (10-20/m2) at two 

 of our stations on Nantucket Shoals (Fig. 7). According 

 to Bousfield (1973), G. nitida prefers rocky bottoms and 

 is found to 50 m. Our collections were from 62 and 77 m 

 on sand bottoms. The scarcity of this species in our sam- 

 ples is most likely due to its preference for rocky sub- 

 strata, which we did not sample. 



Lemboa amithi Holmes 1905 



This species has been reported from Cap* Cod to 

 Florida on wharves, pilings, and eelgrass to depths over 

 20 m (Bousfield 1973). Lembos smithi occurred at two of 

 our stations in Vineyard Sound (Fig. 8) at 26 and 37 m 

 on sand and sand-gravel bottoms in low densities (7- 

 50/m^). The scarcity of this species in our collections is 

 undoubtedly due to its preference for substrata which 

 we did not sample. 



Lemboa webateri Bate 1856 



This species has been reported to occur from Cape 

 Cod to Florida and to 30 m (Bousfield 1973). We col- 

 lected L. websteri in low densities (2-8/m^) at a station 

 in Vineyard Sound and two stations off Norfolk, Va., 

 (Fig. 8). These three stations occurred between 21 and 

 37 m on sand-gravel and sand bottoms. This species 

 occurs most frequently on algal bottoms (Bousfield 

 1973) which explains its scarcity in our soft-bottom sam- 

 ples. 



Leptocheirua pinguia (Stimpson) 1853 



Geographic Distribution. This species has been col- 

 lected between Labrador and North Carolina along the 

 American Atlantic coast (Bousfield 1973; Fox and 

 Bynum 1975). In our collections from the Middle Atlan- 

 tic Bight, L. pinguis occurred in 167 samples at 134 sta- 

 tions between Cape Cod and Cape Hatteras (Fig. 8). 

 The density of this abundant species ranged between 

 2/m'' and 3,300/m^ with a mean density of 300/m^. This 

 species showed a clear trend of decreasing density from 

 north to south, going from 410/m^ in southern New 

 England to 120/m- in the New York Bight and 20/m2 in 

 the Chesapeake Bight. 



Bathymetric Distribution. According to Bousfield 

 (1973), this species is found from the low intertidal to 

 over 250 m. We collected L. pinguis between 6 and 210 

 m. The highest densities (220-690/m2) and the bulk of 

 the samples (114/167) occurred between 10 and 69 m 

 (Table 14). Although this species decreased in abun- 

 dance and frequency to the south, it showed no tendency 

 to change its bathymetric distribution with latitude. 



14 



