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An intensive investigation of the benthic biology of the Porcupine Seabight, to the south-west of Ireland, was carried out by biologists from the Institute of Oceanographic Sciences Deacon Laboratory (IOSDL) between 1977 and 1986. More than 400 benthic samples were obtained during the study using towed gears and corersover the depth range 200 to 4500 m. Transect and time-lapse photography was used extensively. This paper summarises the techniques employed and provides an analysis of the depth and seasonal coverage. In addition a review is provided of available data on the physical, chemical and geological characteristics of the Porcupine Seabight area, including information collected during the IOSDL study. Finally, existing publications based on the study are listed.

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Baited traps deployed at 7800 m in the AtacamaTrench o¡ northern Chile, captured over 400 specimens of Eurythenes gryllus. This is the greatest depth of occurrence reported for the species. Of the 398 specimens available for study, all but three were female, giving a sex ratio very di¡erent from any reported previously. Female specimens measured 29^76 mm in length, and all were immature. Length/frequency distributions based on total length, peraeonite 1 length, and coxa 4 oostegite length were unimodal. Relationships between total length, and peraeonite 1 length, oostegite length, and wet weight were established. Oostegite development appeared to be precocious compared with published data. Subtle di¡erences in peraeon, urosome, gnathopods, coxa 4, peraeopod 7, and epimeron 3 morphology, and the growth of oostegites separate Atacama Trench specimens from previously described material. The morphology exhibited by these specimens lies outside the known variability of E. gryllus, and suggests that this pan-oceanic entity may be undergoing incipient speciation.

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