Fifty years ago, when Professor Seeley gave his masterly description of the Dinosaurs of the Cambridge Greensand, so little was known of these animals that it was naturally impossible to co-ordinate the different remains and to fix their systematic position. Up to 1902 scarcely any attempt was made to review Professor Seeley's conclusions. In that year I tried myself, in a paper, to determine their systematic position, but I find I was mistaken in some points. In 1917 Mr. Bajazid Elmas discovered at Szentpéterfalva some remains of Struthiosaurus that throw much fresh light on the position of this genus, and thus also on the allied genus Acanthopholis. Owing to the war the utilization of these discoveries had to be postponed, but now an attempt can again be made to group the Dinosaurs of the Cambridge Greensand.