Since the publication, about a year ago, in the Transactions of this Society, of my paper on the Lower Devonian Fishes of Gemünden, a review of it has appeared in the pages of Science by Professor Bashford Dean, of New York. In this review Professor Dean endeavoured to throw doubts on the correctness of my orientation of the elements of the dermal skeleton of Drepanaspis Gemündenensis, in the following words:—

“Thus, his grounds seem inadequate for distinguishing dorsal and ventral sides. In no specimen figured is the relation of the dorsal lobe of the tail shown convincingly to be continuous with the so-called dorsal aspect; moreover, the eyes occur on the side which Traquair regards as ventral. Unless additional evidence is forthcoming, it would accordingly seem to me more probable that the ‘labial’ of Traquair was the ‘rostral’ plate, a structure which appears constant in Heterostracans.