232 ON THE DINOSAUR ceTiosaurus leedsi. [Apr. 18. 



1. On Parts of the Skeleton o£ Cetiosaurus leedsi, a Sauro- 

 potlous Dinosaur from the Oxford Chiy of Peterborough. 

 By A. Smith Woodward, LL.D., F.R.S., F.Z.S. 



[Received April 14, 1905.] 

 (Text-figures 39-49.) 



Cetiosaurus is already the best known of European Sauropoclous 

 Dinosaurs, owing to the discovery of associated limb-bones and 

 vertebrae in the Lower Oolite near Oxford*. Much new infor- 

 mation concerning its principal characters, however, is now 

 aflbrded by a large part of a new skeleton disinterred with great 

 skill by Mr. Alfred N. Leeds from the Oxford Clay near Peter- 

 borough. This specimen is so well preserved that, since its 

 acquisition by the British Museum, it has been possible to mount 

 the various bones on ironwork in their natui'al position. An 

 opportunity is thus afFoi'ded for comparing Cetiosaurus more 

 satisfactorily than hitherto with the better known Sauropoda of 

 Jurassic age in Noi'th America. 



The new specimen discovered by Mr. Leeds, and numbered R. 3078 

 in the British Museum Register (text-fig. 39, p. 233), comprises 

 four portions of doi'sal vei'tebrte, some neural spines of the sacrum, 

 four anterior caudal vertebrae, a continuous series of twenty-seven 

 middle caudal vertebrfe, many chevron-bones, the right scapulo- 

 coracoid and fore limb (lacking manus), parts of both ilia, and the 

 left hind limb. It evidently belongs to the species which has 

 already been named Cetiosaurus leedsi on the evidence of a pelvis 

 (Brit. Mus. no. R. 1988) from the same geological formation and 

 locality f. To the same species may also be refei-red four associated 

 anterior caudal vertebrte (Brit. Mus. no. R. 1984) and a portion of 

 the wdaip-like end of the tail (Brit. Mus. no. R. 1967). All these 

 bones have the spongy texture so characteristic of the skeleton of 

 Cetacean mammals, and the vertebral centra are therefore quite 

 difterent from those of the genus Ornit/w2Jsis, to which the species 

 now under consideration was originally assigned. In Ornithopsis 

 the centrum of each vei-tebiu is chambered throughout, and the 

 thin partitions between the small cavities consist of hard, dense 

 bone. 



Dorsal Vertebra}. 



Vertebral centra which seem to belong to the fi-ont and middle 

 of the dorsal series are about as long as deep, and not laterally 

 compressed though somewhat constricted. The centrum of the 



* J. Phillips, ' Geology of Oxfovd ' (1871), pp. 245-294; R. Owen, ' Monograph on 

 the Fossil Reptilia of the Mesozoic Formations ' (Palajont. Soc, 1875), pp. 27-43. 



t J. W. Hulke, "Note on some Dinosaurian Remains in the Collection of 

 A. Leeds, Esq., of Ejebury, Northamptonshire," Quart. Journ. Geol. Soc. vol. xliii. 

 (1887) pp. 695-699. H. G. Seeley, " Note on the Pelvis of Ornithopsis," loc. cit. 

 vol. xlv. (1889) pp. 391-396. 



