SUMMARY: In an earlier paper it was proposed that a second family be re-established within the Mycoplasmatales for those strains not requiring sterol, and the nomenclature of Sabin, who first made this proposal, was followed in the belief that although unsuitable it was valid. It has now been learnt that the generic name Sapromyces is illegitimate, as it is the name of a genus of fungi. It is therefore proposed that the genus be named Acholeplasma in the family Acholeplasmataceae.