Keen retired in 1970 as Professor of Paleontology Emeritus and Curator of Malacology Emeritus. He specialized in the field of malacology. He was a leading authority in the field of malacology. It is also the source of exotic malacology collections of that museum. Those who study malacology are known as malacologists. His interests include mining, mineralogy, palaeontology, chemistry, metallurgy and malacology. The study of dry mollusc shells is called conchology as distinct from malacology (wet specimens). There are collections of entomology, malacology, osteology, ornithology, herpetology, ichthyology and mammalology. One division of malacology, conchology, is devoted to the study of mollusk shells. The study of cephalopods is a branch of malacology known as teuthology. He also collected molluscs on the island and developed an interest in malacology. The Nautilus is a peer-reviewed scientific journal covering research in malacology. The department includes sections that study malacology, ichthyology, crustacea, marine invertebrates and worms. She was called the "First Lady of Malacology". Malacologia is a peer-reviewed scientific journal in the field of malacology, the study of mollusks.