Plate XIV shows two photographs of a model I have recently made in order to show the outward aspect of Peloneustes philarchus, a pliosaur from the Oxford Clay. It is based on the complete mounted skeleton now in the British Museum (Natural History), Cromwell Road, a part of the well-known Leeds collection. This skeleton has a length of 10 ft. 6 in., and my model is 23 in. long, so the scale is roughly about 1:5. No other museum possesses a mounted skeleton of this genus, the nearest thing to which is the Trinacromerum, described as a Cretaceous plesiosaur by Dr. S. W. Williston in his work on Water Reptiles of the Past and Present, Chicago, 1915, where a restoration is shown on p. 89, fig. 42. The specimen is in the Museum of the University of Kansas. This same Leeds collection has given us two fine mounted skeletons of the genus Cryptoclidus, of the family Elasmosauridæ, and now we have also this fine mounted skeleton of Peloneustes, which belongs to the Pliosauridae. Hence it is now possible for geologists to see at a glance the chief characteristics of these two families, and my hope is that this model may be of some use to students of Palæontology. In making the model I have had the advantage of much valuable assistance from my friend, Mr. E. Godwin, an accomplished sculptor, without whose assistance I doubt if it could ever have been completed; for when I attempted to model the head I found a task that was beyond my power to accomplish properly, not having had any training in the art of sculpture.