Cirrate octopods with associated deep-sea organisms: new biological data based on deep benthic photographs (Cephalopoda)

Roper, Clyde F. E., and Walter L. Brundage, Jr. Cirrate Octopods with Associated Deep-Sea Organisms: New Biological Data Based on Deep Benthic Photographs (Cephalopoda). Smithsonian Contributions to Zoology, number 121, 46 pages, 53 figures. 1972.—Twenty-seven photographs from seven deep-sea localities in the North Atlantic reveal cirrate octopods in their natural habitat. The photographs demonstrate that these octopods are benthopelagic, living just above the bottom at depths of 2,500 to greater than 5,000 m. Typical cephalopoda locomotion is exhibited as well as a drifting or hunting phase, and possibly a pulsating phase. Animals range in size from approximately 10 to 128 cm in total length, and up to 170 cm across the outstretched arms and webs. Scale size was determined mainly by a new technique termed shadow geometry, introduced here. Observations on shading ("coloration") indicate the possibility of "reverse coloration" on some specimens. Cirrates are more abundant in the Virgin Islands Basin than in other areas sampled. Additional photographs of plant debris, animals and lebensspuren (evidence of organisms in the sediment) suggest that the abundance level of benthic and benthopelagic organisms is related to the presence of plant material of shallow-water origin. Librar