A review is presented of the genera and species, both living and fossil, comprising the Superfamily Kraussinoidea and of their geographic and stratigraphic distributions. Two new fossil species are described, Kraussina chilensis and Megerlina miracula, from the Miocene of Chile and New Zealand respectively. The ontogenetic development of the brachidium in each of the four kraussinid genera is described and on the basis of recognised differences it is proposed that a new taxonomic subdivision is made that places Megerlia in a new subfamily Megerliinae, distinct from the other three genera in the existing subfamily Kraussininae Dall. The loop ontogeny of kraussinoids is compared with that of other terebratellidines and a phylogenetic linkage between kraussinoids and laqueoids is suggested.