I think it is an oversimplification to say that conchologists study "just the shell" while malacologists study "the whole organism". It is certainly true that a conchologist concentrates on the shell. However, a malacologist's research may focus on any aspect of molluscan behavior, systematics, physiology, anatomy, or biochemistry, and some such studies will inevitably concentrate on the shell. A conchologist, in my opinion, is primarily a hobbyist, while a malacologist is first and foremost a scientist. The term "hobbyist" does not suggest a lack of in-depth knowledge or expertise. On the contrary, many advanced conchologists undoubtedly know more about their subject matter - shells - than many malacologists do. However, their emphasis is not on scientific research. That, I think, is the dividing line between conchology and malacology. A researcher who is investigating the protein content or trace elements or crystalline configuration or mechanical strength or rate of dissolution of shells is certainly a malacologist, even though he/she is studying "just the shell". Paul M.