Five species of Cypria 1 new), 2 species of Physocypria, 5 species of Cyclocypris (1 new), the monotypic Reticulocypris n. gen. , of the Cyprinae, 4 species (1 new), 4 species of Ilyocypris (2 new), 13 species of Cytheridae (8 new) and Darwinula aurea are described in detail. For the first time, Cytherissa is recorded from the Americas. The assemblages from each locality are discussed with regard to stratigraphic and geographic position. Confirmation of the stratigraphic value of certain species confined to stages of the Pleistocene epoch must await detailed studies of the assemblages of other areas. Part I considered the subfamilies Candoninae and Cyprinae, and synthesized ecologic data on assemblages and critical species.