A-23 



mostly composed of a silty substrate and areas of consolida- 

 ted clay outcrops. It is not nearly as heterogeneous as the 

 wall of Oceanographer Canyon. Two corals, the gorgonian 

 Aoanella arhusaula and the alcyonacean Anthomastus gvandi- 

 f torus , both of which are found of soft substrates, dominate 

 the shallower part of the wall (850 to 1050 m) . Deeper 

 several echinoderms, an Ophioaantha sp., Ophiomusium tymani 

 and the urchin Phormosoma placenta dominate the fauna. The 

 gorgonian Paramuvicea bovealis was common between 14 50 to 

 1500 meters. In the axis Hyalinoecia artifex dominated the 

 fauna between 1150 to 1500 meters. The corals seen were 

 Anthomastus agassisii and Desmophyllum ovistagalti , both 

 restricted to hard substrates. From 1500 to 1550 meters D. 

 cristagalli dominated the fauna, whereas deeper Ophiomusium 

 lymani was dominant. 



The fauna on the wall of Corsair Canyon was heavily 

 dominated by coral (Figure C7). These were all corals res- 

 tricted to soft substrates. The delicate bush-like gorgonian 

 Aaanella avbusoula was a prominent constituent of the fauna 

 between 600 to 800 meters. From 800 to 1000 meters the fauna 

 was dominated by the corals Anthomastus gvandif torus and a 

 species of Pennatuta. The wall of Corsair Canyon, as well as 

 that of Heezen Canyon, is not nearly as heterogeneous in 

 terms of substrate variability as that of Oceanographer 

 Canyon. Thus, particular species tend to dominate the taxa , 

 whereas the fauna on the wall of Oceanographer Canyon is 



