Freshwater Snails (Mollusca: Gastropoda) of North America

摘要

Freshwater gastropod mollusks are represented in North America (north of Mexico) by 15 families, 78 genera and, as treated in this manual, 499 species. They are grouped into two large subclasses, the gill-breathing, operculated Prosobranchia and the lung-breathing, non-operculated Pulmonata. The prosobranch snails are represented by 49 genera and 349 species, and the pulmonate snails by 29 genera and 150 species. Systematics are not well worked out in many groups, which makes a definitive listing of species somewhat arbitrary at this time.