Reproduction and Embryology of Nautilus

In the past 15 years, there has been tremendous progress in our understanding of many aspects of Nautilus biology. This progress is due in part to an increase in the number of investigators now interested in this genus, but is largely due to successful collection and aquarium culture techniques (Carlson, 1979; Mikami et al., 1976) (see also Chapter 35). When I began writing this chapter, I jokingly offered to leave four blank pages to cover what was then known about the embryonic development of Nautilus. That same afternoon, I opened some neglected egg capsules and found the first living Nautilus embryo (Arnold and Carlson, 1986). What follows is more a progress report than an attempt to present definitive data and meaningful interpretations.