The new genus Eopleurophorus and the new subgenus Springeria are introduced, and thirty-seven species and subspecies are described, seventeen of which new. Some forms show apparent relation to British Lower Carboniferous species, but the majority are related to American Mississippian Pennsylvanian forms. Morphology and taxonomic status of the genera Solen, Edmondia, Nuculopsis, Phestia, Polidevcia, Yoldia, Parallelodon, Leptodesma, Pteronites, Sedgwickia, Schizodus, Sanguinolites, Allorisma, Tellinomorpha, and Pleurophorus are discussed.