On an associated Series of Cervical and Dorsal Vertebræ of Polyptychodon , from the Cambridge Upper Greensand, in the Woodwardian Museum of the University of Cambridge

Abstract

T he rarity of vertebræ of Polyptychodon in the Cambridge Greensand is out of all proportion to the relative abundance of teeth. In the Woodwardian Museum alone more than a hundred teeth are arranged in illustration of the dentition of the genus, about half of which (probably the remains of one animal) were found at a Phosphatite washing on the Huntingdon Road. Many hundreds of teeth have probably been collected, all in a state of black mineralization; and these can only be referred to several individuals. The vertebræ collected do not appear to be the remains of more than two individuals; and these probably represent two species. They consist of the bones so admirably described by Professor Owen in the publications of the Palæontographical Society for 1860, which were found near Haslingfield, and the associated series of remains from the Huntingdon Road, belonging to a somewhat smaller animal, catalogued at p. 45 of my ‘Index to Aves, Ornithosauria, and Reptilia,’ which latter are the subject of the present notice. All the vertebræ are in a condition of somewhat pale mineralization. I mention this fact, because it is within my own knowledge that different parts of the same specimen are sometimes differently mineralized, and the condition has no importance as indicating a native or derivative origin of the fossils. The Atlas and Axis. Professor Owen's figure represents the atlas and axis as being more excellently preserved than they are, and as showing a clear separation between the atlas and axis, which is