36 MR. R. LYDEKKER ON DINOSAURS OE THE WEALDEN 



3. Contributions to our Knoivledge of the Dinosaurs of the Wealden 



and the Sauropterygians of the Purjbeck and Oxeord Clay. 



By R. Lydekker, Esq., B.A., F.G.S., &c. (Eead November 6, 



1889.) 



[Plate V.] 



The present communication is divided into four sections — the first 

 giving an account of Iguanodont remains obtained from the Wad- 

 hurst Clay near Hastings subsequently to the writer's previous 

 paper on this group ; the second devoted to the description of a 

 metatarsus of a Megalosaurian from the same deposits ; the third 

 recording some vertebrae of a Sauropterygian from the Purbeck of the 

 Isle of Portland ; while the fourth gives a description of an associ- 

 ated series of remains of a Pliosaur from the Oxford Clay near 

 Peterborough. 



I. The Iguanodonis of the Wadhurst Clay. 



Two years ago I brought under the notice of the Society* certain 

 remains of large Iguanodonts collected by Mr. C. Dawson, P.G.S., 

 from the Wadhurst Clay (Lower Wealden) in the neighbourhood of 

 Hastings, and now preserved in the British Museum. Among these 

 a left ilium and some associated vertebrae presented such differences 

 from the corresponding bones of Iguanodon Mantelli and /. bernis- 

 sartensis, that I felt justified in regarding them as the types of a 

 distinct species, for which the name /. Daiusoni was proposed. I 

 was careful at that time to mention that these specimens only were 

 taken as the types, and it is fortunate that this was done, since it 

 now appears that the sacrum and ischium which, in the absence of 

 any evidence to the contrary, were referred to the same species, 

 belong to a distinct form. 



Since the publication of that paper Mr. Dawson has assiduously 

 continued his collecting in the quarries of the Wadhurst Clay, the 

 result of which has been the acquisition of a very large series of new 

 specimens — many of them being associated — although, unfortu- 

 nately, he has not yet succeeded in obtaining a skull. These speci- 

 mens, all of which are preserved in the British Museum, indicate 

 the existence in the Lower Wealden of two Iguanodonts which 

 appear to be distinct from /. Daiusoni, and of which I have given a 

 preliminary notice in the ' Geological Magazine 't, under the names 

 of /. Fittoni and /. hollingtoniensis. Before, however, proceeding to 

 give a fuller account of some of the specimens on which these species 

 are founded, it will save trouble to formulate a brief summary of the 

 chief characters of /. Daiusoni, as derived from the type specimens, 

 supplemented by others taken from an imperfect skeleton recently 

 acquired by the British Museum. 



* Quart. Jouru. Geol. Soc. vol. xliv. pp. 46-52 (1888). 

 t Decade 3, vol. vi. pp. 354, 355 (1889). 



