Abstract
This study originated as an inquiry, some twenty years ago, into what names should be employed for species of coccoid Myxophyceae found in general collections of algae from various parts of the world. Gradually we accumulated and examined many thousands of specimens. Equally gradually it became apparent to us that only a carefully executed revision of the group, with sufficient attention paid to the morphological variation and life history of each species and with strict adherence to the stern discipline of the science of historical taxonomy, would produce a classification and a nomenclature which would satisfy our desire.