Coelatura Conrad, 1853 is the valid name for the genus of unionid bivalves emended to Caelatura by Simpson (1900). The family-group name Caelaturinae Modell, 1942 must be corrected lo Coelaturinae Modell. Caelatura Conrad, 1865 is the valid name for the genus of barleeid gastropods renamed Actaeonema Conrad. 1865 Coelatura Pfeiffer, 1877, Coelalura, von Martens, 1880, Caelatura Germain, 1921 and Ariocaelatura Germain, 1921 are objective synonyms of Plegma Gude, 1911, a genus of hexlixarionid gastropods. Confusion among these names has resulted from the difficulty in distinguishing between the "ae" and "oe" diphthongs when they are printed as ligatures. The ligature for "ae" in some typefaces is used as an "oe" in others. The only way to be sure of an author's intentions is to compare words of known spelling.