A-30. 



The dominant taxa at these depths are similar to those 

 reported by Haedrich, Rowe and Polloni (1975). Geryon 

 quinquedens , Glyptocephalus cynoglossus and Hyalinoeoia 

 artifex were among the seven top ranking species in the 

 middle zone (393-1095 m) of their trawl study on the slope 

 south of New England. Surprisingly, Hyalinoeoia was absent 

 from Alvin Canyon in their study, whereas in the present 

 survey three out of five occurrences were in canyons. 



The notable exceptions to the species generally found 

 within this middle depth zone are the faunas of the walls of 

 Heezen and Corsair Canyons. The fauna of the upper wall of 

 Heezen Canyon (850-1100 m) is dominated by two corals Antho- 

 mastus grandiflorus and Pennatulasp. (6). These corals are 

 not independently distributed and almost always occur 

 together. Both are restricted to soft substrates. This 

 assemblage is also found on the wall of Corsair Canyon (750- 

 950 m) , at 1450 meters in Oceanographer Canyon, and deeper in 

 the axis of Norfolk Canyon (1500-1600 m and 2150-2350 m) . The 

 fauna of the wall of Corsair Canyon is mainly composed of two 

 dispecific end-members, the Anthomastus grandif torus and 

 Pennatula sp. assemblage (6) and two other corals Acanetla 

 avbuscula and a sea pen that may be Distichoptilum graaile 

 (assemblage 8). Both assemblages are restricted to soft sub- 

 strates. A soft coral resembling Aaanella avbuscula was also 

 seen at 2300 meters at DWD-106 and from 1750 to 1900 meters 

 in an area south of Norfolk Canyon. Anthomastus grandiflorus, 



