The genus of Carboniferous corals, forming the Chœtetes of Fischer, has long been known to palaeontologists under, at least, three generic names, viz., Favosites, Chœtetes , and Alveolites. They were first described by Fleming, in 1828, in his “British Animals,” where he placed them in Lamarck's genus, Favosites. In 1837, Fischer established the genus Chœtetes for a Russian Carboniferous coral— C. septosus , now believed to be identical with one of Fleming's species. Count Keyserling, in 1846, removed Fleming's species from Favosites , from their not having perfect walls for their corallites, and from the absence of mural pores in their walls as found in Favosites , and placed them with Fischer's Chœtetes In 1851, Professor M'Coy, in his “British Palaeozoic Fossils,” accepted Fischer's genus for Fleming's species, but in the same year, Milne Edwards and Jules Haime, in their Monograph on “Fossil Corals,” issued by the Palaeontographical Society, removed Fleming's species from Chœtetes into Alveolites of Lamarck, retaining at the same time Fischer's genus Chœtetes for his species C. radians , which, as above stated, is now believed to be identical with Fleming's British form— C. septosus. Chœtetes , however, is now the genus most generally accepted by palaeontologists for this entire group of Carboniferous corals. During last year, I was led to make an independent examination of the structure of these corals, by means of transparent sections prepared by myself for examination under the microscope. I was induced to do this, owing to a somewhat bitter dispute which had arisen between Mr. James Thomson, F.G.S., of This 250-word extract was created in the absence of an abstract