On certain Ornithosaurian and Dinosaurian Remains

Abstract

[P late V.] I May state, by way of introduction, that I am indebted to my friend Professor O. C. Marsh for the correct determination of the interesting reptilian bones forming the subject of the present communication. I. Ornithosaurian Quadrates . When engaged in compiling Part I. of the ‘British Museum Catalogue of Fossil Reptilia and Amphibia,’ I was considerably puzzled with three imperfect bones from the Kimeridge Clay of Weymouth. Eventually I considered that they represented a peculiarly modified ulnar metacarpal of an Ornithosaurian; and they were accordingly entered at page 41 of the volume cited (Nos. 43034, 44183, and 41179) as the distal extremities of that bone. It was mentioned at page 40 of the same volume that these bones differed from normal specimens of the ulnar metacarpal in having a flat bony plate attached to one of their lateral surfaces, which I considered might have aided in the support of the patagium. The resemblance of the free trochlear extremity of these bones to that of the distal extremity of the ulnar metacarpal of an Ornithosaurian is, indeed, very striking; but, on seeing them, Professor Marsh at once said that they were Ornithosaurian quadrates. On comparison with the quadrate of the skeleton of Rhamphorhynchus Cuvieri preserved in the Museum, and also with that of Scaphognathus Purdoni†, it is quite evident that they belong to the right side of the skull. The distal extremity of each forms a deeply-grooved oblique trochlea, above which there is a nearly quadrangular shaft. To the