Dr. Ingvar Kristensen, born on 11 February 1918, died on 24 March 1996. He had a distinguished career as a marine biologist in the Netherlands and in the Netherlands Antilles. He was member of the staff of the NIOZ (Netherlands Institute for Sea Research, Den Helder-Texel, 1946-1956, 1964-1982), and was director of the CARMABI (Caribbean Marine Biological Institute, Curaçao, 1960-1964, 1970-1981). He was also intensely involved in nature conservation, particularly in the Caribbean. In addition he was an accomplished aquarist and orchid lover. His malacological research was mainly focussed on ecology and physiology of marine molluscs. This obituary concludes with a list of his malacological publications.