METHODS 



The collections upon which this study were based con- 

 sisted of over 70,000 amphipods from 669 quantitative 

 grab samples from 563 stations between Cape Cod, 

 Mass., and Cape Hatteras, N.C. (Fig. 1). The basic pat- 

 tern of stations was a sampling grid with stations spaced 

 18 km apart, but there were many additional stations 

 particularly in the northern portion of the study area. 

 The grid pattern resulted in a predominance of samples 

 in the open shelf habitat, because of its substantially 

 greater area, with fewer stations being taken in es- 

 tuarine and deep-sea habitats. Station data including 

 latitude, longitude, date, gear type, depth, and sedi- 

 ment type are listed in VVigley et al. (1976°). The general 

 patterns of bathymetry and sediment distribution are 

 shown in Figures 2 and 3. 



VVigley and Theroux (In press) subdivided the Middle 

 Atlantic Bight into three subareas: Southern New 

 England, the New York Bight, and the Chesapeake 

 Bight (Fig. 2). These subareas are useful in making geo- 

 graphic comparisons and will be followed in this pap>er. 



Collections were made with three different sized 

 grabs: the Campbell grab (0.56 m^), the Smith- 

 Mclntyre grab (0.1 m^), and the Van Veen grab (0.2 m^). 

 The Campbell grab was used at 355 stations, the Smith- 

 Mclntyre at 195 stations, and the Van Veen at 13 sta- 

 tions. Each sample provided material for both biolog- 

 ical and geological analyses. 



The methods of shipboard sample processing are de- 

 scribed in detail by Wigley and Theroux (In press). All 

 grab samples were washed over a 1 mm mesh sieve and 

 preserved in buffered Formalin. In the laboratory, the 

 amphijjods were sorted out of the samples along with 

 other major taxa, transferred to ethanol, identified, and 

 enumerated using dissecting microscopes. The sptecies 

 counts were adjusted to a per m^ basis taking into ac- 

 count the sampler size and any subsamples removed. 

 The density data for each sj>ecies were correlated with 

 depth, sediment type, and latitude in an effort to 

 elucidate major patterns of abundance. 



SYSTEMATIC ARRANGEMENT 



The systematic arrangement and terminology follow 

 Barnard ( 1960, 1969, 1972, 1973) at the genus and family 

 levels. Bousfield's (1977) recent work on gammaridean 

 systematics was consulted, but we chose to follow Bar- 

 nard (1969) in order to maintain a consistent 

 hierarchical arrangement. The species names are 

 primarily as in Bousfield (1973). The list of species in 

 their resp>ective families is as follows: 



Order AMPHIPODA 

 Suborder GAMMARIDEA 



■■Wigley. R. L., R. B. Theroux, and H. E. Murray. 1976. Macrobenthic 

 invertebrate fauna of the Middle Atlantic Bight Region. Part 1. Collection 

 data and environmental muasurementa. Northeast Fiah. Cent. Rep.. 

 Woods Hole. Mass.. M p. 



Family AMPELISCIDAE 



Ampelisca abdita Mills 1964 

 Ampelisca agassizi (Judd) 18% 

 Ampelisca decliiitatis Mills 1967 

 Ampelisca macrocephala Liljeborg 1852 

 Ampelisca uncinata Chevreux 1887 

 Ampelisca uadorum Mills 1963 

 Ampelisca uerrilli Mills 1%7 

 Byblis gaimardi Kn^yer 1846 

 Byblis serrata Smith 1873 

 Haploops similis Stephenson 1925 



Family ARGISSIDAE 



Argissa hamatipes (Norman) 1869 

 Family BATEIDAE 



Batea catharinensis Miiller 1865 

 Family CALLIOPITOAE 



Calliopius laeuiusculus (Kn^yer) 1838 



Family COROPHIIDAE 



Corophium acutum Chevreux 1908 

 Corophium crassicorne Bruzelius 1859 

 Corophium tuberculatum Shoemaker 1934 

 Gammaropsis maculatus (Johnston) 1827 

 Gammaropsis nitida (Stimpson) 1853 

 Lembos smithi Holmes 1905 

 Lembos websteri Bate 1856 

 Leptocheirus pinguis (Stimpson) 1853 

 Leptocheirus plumolosus Shoemaker 1932 

 Microprotopus raneyi Wigley 1966 

 Neohela monstrosa (Boeck) 1861 

 Photis dentata Shoemaker 1945 

 Photis macrocoxa Shoemaker 1945 

 Protomedeia fasciata Kn^yer 1842 

 Pseudunciola obliquua (Shoemaker) 1949 

 Rildardanus laminosa (Pearse) 1912 

 Siphonoecetes smithianus Rathbun 1908 

 Unciola inermis Shoemaker 1945 

 Unciola irrorata Say 1818 

 Unciola laticornis Hansen 1887 

 Unciola leucopis (Kr(^yer) 1845 

 Unciola serrata Shoemaker 1945 

 Unciola spicata Shoemaker 1945 

 Unciola sp. A 

 Unciola sp. B 



Family EUSIRIDAE 



Pontogeneia inermis (Kr^yer) 1838 

 Rhachotropis inflata (G. 0. Sars) 1882 



Family GAM M ARID AE 



Casco bigelowi (Blake) 1929 

 Elasmopus levis Smith 1873 

 Eriopisa elongata (Bruzelius) 1859 

 Gammarus annulatus Smith 1873 

 Gammarus daiberi Bousfield 1%9 

 Gammarus mucronatus Say 1818 

 Gammarus tigrinus Sexton 1939 

 Maera danae Stimpson 1853 

 Melita dentata (Kr(/yer) 1842 

 Melita nitida Smith 1873 

 Melita sp. A 



