The Cambridge Pterodactyles first attain prominence in scientific literature in the year 1859. Professor Owen had figured (plate 32, fig. 6-8) fragments of bones in the Palæontographical Society's Monograph for 1851; the distal end of a large ulna (fig. 6); the shaft of a phalange of the wing-finger, probably the first (fig. 7); and the upper portion of the shaft of a small humerus showing part of the radial crest (fig. 8). Inadvertently the last specimen was referred to the Lower Greensand. But although fragments of humerus of Pterodactyle and vertebræ of Pterodactyloid animals have in the last few years been gathered from the Potton Sands, those deposits were believed to be barren of fossils when Prof. Owen wrote; and all the Pterodactyles yet made known from near Cambridge were collected from the Cambridge Upper Greensand. Among the earliest successful collectors were Mr James Carter, the Rev. H. G. Day, St John's Coll.; Prof. G. D. Liveing, St John's Coll.; the Rev. T. G. Bonney, St John's Coll.; and Mr Lucas Barrett, Trin. Coll.; and the Rev. Prof. Sedgwick, Trin. Coll., on behalf of the Woodwardian Museum. Mr Day and Mr Bonney both presented every specimen from their cabinets which could enrich the University collection. And in the last ten years the Woodwardian Museum has acquired, through the skillful collecting of the Messrs Farren, the present materials. The associated sets of bones were formed by William and Robert Farren, who, obtaining the specimens from day to day as they were discovered, were enabled to put together such parts of the skeleton as remained together on the sea-bottom. These collections will hereafter be used for the elucidation of species. They are the only materials which can give the proportions of the Cambridge Ornithosaurians, and the contrast of aspect which distinguished the living animals from those from other rocks. The other collections of these fossils are those of Mr William Reed and Mr J. F. Walker at York, the Museum of Practical Geology, and the British Museum.