Some Bathyal Pacific Amphipoda Collected by the U . S . S . Albatross

SEVERAL BATHYAL Amphipoda from the U.S.S. "Albatross" exped itions of 1888 onward (Holmes, 1908; Shoemaker, 1925) remained to be determined in the collections of the U.S. National Museum, and the results of the ir study are presented here. Increasing interest is being shown in faunas on bottoms of 200-2000 m. Although these depths comprise only 8.5% of the world 's sea-floor, they perhaps suppOrt the remnants of the ancient abyssal fauna occupying depths greater than 2000 m prior to the Tertiary cooling of the seas (Madsen, 1961; Barnard, 1961, 1962; and their bibliographies) . Bathyal benthic depths outside of the Norwegian polar basin have not been well explored for amphipods, so that any records are of great interest. These early Albatross collections, although small and widely scattered, contain very well-preserved and intact specimens of seven previously known and six new species. Of especial interest is another record of Mesopleustes abyssorum Stebbing and the opportunity to discuss its relationship among three families that it intergrades. The question of speciat ion in the genus Eusirella is reopened. No depth is known for a new species of Melita, but its poorly pigmented eyes may indicate a deepwater origin. Not all of the species recorded here are benthic, the members of the genera Rhachtropis, Koroga, Eusirella, Cyclocaris, and Parandania being bathypelagic or demersal.