Foraminifera were studied in 18 small gravity cores and 6 trawl samples from the area of the South Sandwich trench. The samples ranged in depth from 558 to 7,700 meters. Nine core samples were collected in a traverse across the central trench area from 57½° to 59° S. Lat.

Foraminiferal trends are discussed in terms of groups of species with similar depth distributions. Calcareous Foraminifera (Cassidella sp. group) may be as abundant as 40 per cent of the foraminiferal fauna between 558 and 805 m., but gradually decrease with depth to insignificant numbers below 1,058 m. As calcareous Foraminifera decrease with depth, Haplophragmoides membranaceum group increases and becomes characteristic of the zone between 1,244 and 1,841 meters. Textularia antarctica group remains remarkably constant throughout these depths but also declines below 1,841 meters. Samples from the lower bathyal zone (2,976-4,800 m.) contain large numbers of species including Cyclammina pusilla, Cribrostomoides subglobosus, and Martinottiella communis. A diverse Trochammina fauna (Troc ammina sp. A group) is especially characteristic.

The upper abyssal fauna (1,076-1661 m.) is a reduced lower bathyal fauna dominated by Trochammina antarctica, a species common at all depths. A core and a trawl from 7,700 meters both were barren of Foraminifera.

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