1. Anatomical descriptions in this study especially focused on three-dimensional morphological data at the gross and SEM levels. As a result, a number of new characters were revealed in the buccal apparatus and other organs. These characters clearly show discrete states and distinct taxonomic distribution, suggesting potential for contributing toward resolving phylogeny. Thus, some of the vast gaps in gastropod anatomy have been filled by the descriptions in this study.

2. Character tracings on the cladogram resulted in "acceptable" changes in some characters, but "implausible" transformations in others. One example is the change in most pallial characters from unpaired to paired conditions. Although this pattern is opposite to the traditional view, there is no positive theoretical reason why the symmetry of gastropod organs should be assumed absolutely irreversible. In any case, assumptions of homology should be reconsidered, as with any homoplastic result.

3. Other major aspects of gastropod evolution are represented by transformations from complex to simple, from opened to closed, or from weakly organized to well-organized conditions (especially in digestive, reproductive, and nervous system). These share the common feature that primitively intricate conditions are elaborated into functionally sophisticated, compact forms through re-organization.

4. Among shell characters, protoconch morphotypes are relatively consistent with the phytogeny inferred from soft parts. This is in clear contrast to the general observation that macroscopic characters of the gastropod teleoconch are less useful to higher-level phytogeny. More extensive studies should be made relative to larval anatomy and reproductive biology.

5. For future works, microstructural investigations will increase in importance not only in anatomical descriptions but also in conchological and paleontological research. Anatomical observations should also be extended to the larval stages of various taxa in terms of ontogeny and phylogeny or heterochrony. Progress toward better understanding of molluscan evolution can be achieved by a rich accumulation of high-quality data, as well as technical advances in analytical methodology.