Thirty-nine taxa, many of them index species, are described and illustrated; their biostratigraphic and chronostratigraphic significance are related to tectnostratigraphic settings.

The systematic revision herein of several cool water cymatiid genera provides the basis for biogeographic studies and a possible scheme of phylogenetic affinities. Of 45 related and convergent forms described in these genera, 20 are recognized as distinct taxa in Argobuccinum, Fusitriton, Mediargo, and Priene. Morphologic differences are considered in the light of growth changes, intraspecific variability, and mode of preservation. Ecologic and distributional data are summarized.