Bulletin of Zoological Nomenclature 117 MEGALICHTHYS AND RHIZODUS (PISCES, RHIPIDISTIA) : PROPOSAL FOR THE STABILIZATION OF THESE GENERIC NAMES. Z.N.(S.) 1690 By Keith Stewart Thomson (Department of Zoology, University College London) Recent studies on the relationships of rhipidistian fishes (e.g. Thomson, Bull. Mus. comp. Zool., Harvard, 131 : 285-312) have made necessary a request for formal stabilization of the common usage of the generic names Megalichthys and Rhizodus. 1. The genus Megalichthys was named by Agassiz (Agassiz in Hibbert, 1835, Trans. Roy. Soc. Edinburgh 13 : 169-282) for remains of a large "sauroid" fish that had been discovered in the Carboniferous limestone quarry at Burdiehouse near Edinburgh. The remains of this " large fish " had been mentioned in several contexts (such as Hibbert's report to the Geological Section of the British Association for the Advancement of Science in 1834, published 1835, and in Agassiz's address to the same meetings). But these instances do not constitute definite "indication" in the sense of the 1961 International Code of Zoological Nomenclature. Hibbert's was the first scientific account and the first proper description. The remains consisted of some large teeth, some smaller teeth, and scales of assorted sizes. These specimens had been shown, during the 1834 British Association meetings, to Agassiz who was then in Great Britain collecting material for his " Poissons Fossiles ". At the time there was much con-troversy in scientific circles about whether such remains were sauroid (i.e. resembling reptiles) or saurian (actually pertaining to reptiles). Agassiz and Buckland decided to settle the matter and, subsequently visiting various public museums in England, they found in the Leeds Museum a rather complete head and partial trunk (now in the British Museum (Natural History), no. P.42516) of a sauroid fish from the Yorkshire coalfields. This, they decided, was identical with the Burdiehouse material. The problem of the nature of the Burdiehouse remains was thus solved and ". . . after M. Agassiz had . . . estab-lished that these teeth and certain other osseous remains of Burdiehouse belonged to a sauroid fish ... he considered it as a new genus to which he gave the name Megalichthys; and to the species found at Burdiehouse he added the name of Megalichthys hibberti. " (Hibbert, Trans. Roy. Soc. Edinburgh 13 : 202). 2. Fleming in October 1835 (some eight months after Hibbert's description, above) described some remains of Megalichthys hibberti (now in Royal Scottish Museum, Edinburgh, no. 1950.38.58) under the name of Ichthyolithus clack-manensis {Edinburgh New Philos. Jour. 191 : 314-316). 3. In 1837 Sir Philip Egerton {A systematic and stratigraphic catalogue of the fossil fishes in the cabinets of Lord Cole and Sir Philip Grey Egerton . . . Revised Edition, London. 20 pp.) uses the name Holoptychius hibberti in addition to the name Megalichthys hibbertii* for specimens in his possession * The spelling of the specific name hibberti or hibbertii seems to have varied with the preference of the author. Bull. zool. Nomencl., Vol. 23, Double Part 2/3. July 1966.
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