R. D. Purchon 
Biology of the Mollusca [PDF ebook] 

Reviews the most important literature on the functional morphology and natural history of molluscs over a period of half a century, from 1925 to the present day, and draws extensively upon authoritative papers published mostly in the English language in a large number of international journals during this period. By these means it is hoped to provide an anthology of what is most interesting in the literature in a number of selected topics. Appendices give some practical assistance for the dissection of selected examples