More than sixty years have now elapsed since the publication of the classical monograph of MM. Milne-Edwards and Jules Haime, “Les Polypes Fossiles des Terrains Palæozoïques.” It can only be expected that many of the original descriptions of species in that work have for long been in need of amplification and revision. This applies with added force to the corals of the Carboniferous Limestone, in view of the impetus given to the palæontological study of that formation, by the vigorous revival of zonal work witnessed in the last few years. Those species in most urgent need of revision belong to the lower, or Tournaisian division of the Limestone, since their satisfactory determination affords a basis for evolutionary studies on the succeeding faunas, and an attempt is here made to deal with a few of these forms.