On the Dentition of the Petalodont Shark, Climaxodus

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Abstract
The dentition of the Petalodont sharks is still very imperfectly known. It has hitherto been satisfactorily observed only in the highly-specialized Janassa bituminosa from the Upper Permian (Kupferschiefer and Marl Slate) of Germany and England. Nearly all the other species and genera are represented in collections merely by isolated teeth. It is, therefore, of interest to examine the comparatively well-preserved dentition of a new Lower Carboniferous Petalodont, which has been kindly lent to me by Dr. William Eagle Clarke, Keeper of the Natural History Department of the Royal Scottish Museum, Edinburgh. The specimen was obtained from the Calciferous Sandstone of Calderside, near East Kilbride (Lanarkshire), and was presented to the Royal Scottish Museum in 1892 by Mr. John B. Wise, of Glasgow. It was regarded by the late Dr. R. H. Traquair as belonging to a new species of Janassa , which he named J. wisei but it has not so far been described or discussed. The hard shale in which the two jaws are preserved has split along the plane of the mouth, so that the dentition of each is exposed from the oral aspect, as shown in Pl. I. Of the cartilages only fragments remain behind and partly below the teeth, especially in the wider of the two jaws (which is here regarded as the upper). Nearly all the teeth seem to be present in the narrower or supposed lower jaw; but some of the small anterior teeth are broken away from the front of the opposing jaw, and

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