Analysis of dorsal carapace characters of fossil and extant genera of the Calappidae sensu lato supports Bellwood's (1996) assignment of the group into four families based upon phylogenetic analysis, which was also supported by previous larval and morphologic studies. The Calappidae sensu stricto, Matutidae, and Hepatidae, recognized by Bellwood (1996), embrace both fossil and extant genera. The Orithyiidae is known from a single extant genus. Additionally, the Necrocarcininae Förster, known only from extinct genera, is elevated to family status. New taxa include Mursia aspina and Eriosachila rossi. Zanthopsis rathbunae Kooser and Orr, 1973, is here referred to Eriosachila orri, n. comb. and nomen novum. Emended descriptions are given for Mursia yaquinensis Rathbun, 1926, and Necrocarcinus hannae Rathbun, 1926. Biogeographic analysis indicates that each family has a distinct origination and dispersal history independent of the other families. Ecologic information for each group suggests that climatic preferences for the extant families have either remained relatively stable since the appearance of each family in the Tertiary or were broader in the past.