46 ME. R. LTDEKKER ON A NEW 



6. Note on a new Wealden Iguanodont and otlier Dinosaurs. 

 By E. Lydekker, Esq., B.A., E.G.S. (Eead Noyember 23, 1887.) 



[Plate III.] 



Introductory. — The primary object of this eommunicatioii is ta 

 bring to the notice of the Society numerous remains of an appa- 

 rently new Iguanodont Eeptile obtained by Mr. C. Dawson, P.G.S., 

 of St. Leonards, from the "Wadhurst Clay (one of the beds of the 

 Hastings Sand, or lower division of the Wealden), and recently 

 acquired by the British Museum; and also a maxilla from the 

 Wealden of the Isle of Wight, apparently referable to Ornitliopsis. 

 Having, however, recently examined the whole of the collection 

 of Dinosaurian remains preserved in the Museum, in the course 

 of the preparation of the first part of the forthcoming ' Catalogue of 

 Possil Eeptilia' of the collection, I have also made certain observa- 

 tions regarding other members of the order, which may be con- 

 veniently recorded at the same time. 



Iguanodonts. — Commencing with the Iguanodonts, I may first of 

 all observe that I fully concur in the view which M. Dollo informs 

 me he now takes as to the specific identity of Iguanodon hernissart- 

 ensis and /. Seelyi ; and, although the original description is very 

 meagre and unaccompanied by a figure, I think we ought to adopt 

 the former and earlier name for the species which has been so well 

 described by the Belgian naturalist. The British Museum possesses 

 a considerable series of the remains of this species, many of which 

 were referred by Sir E. Owen to Cetiosaurus and PelorosauruSy 

 while others have been described under the name of Iguanodon 

 Mantelli. 



In addition to the two "Wealden species of Iguanodon (/. Mantelli 

 and /. hernissartensis) and the perfectly distinct genus HypsilopJiodon, 

 Prof. Seeley has described other Iguanodont vertebrae from the same 

 formation in the Isle of W ight, under the name of Splienosjpondylus * ; 

 while at the recent meeting of the British Association he has pro- 

 posed to refer /. Prestwichi, Hulke t, of the Kimeridge Clay, to a 

 fourth genus under the name of Cumnoria. 



With regard to Sj)he7iosj)ondylus, I find from specimens in the 

 Museum that several of the anterior dorsal vertebrae were opistho- 

 coelous, while those later in the series retain a trace of the same 

 feature ; and from this circumstance I am disposed to regard this 

 form as not improbably entitled to generic distinction from Iguan- 

 odon, and showing some resemblance to the genus usually known 

 as Hadrosaurus (but of which the correct name is Trachodon), 

 characterized by all the dorsals being opisthoccelous. The later 



=*= Quart. Journ. Geol. Soc. vol, xxxix. p. 55 (1883). 

 t Ibid. yol. xxxvi. p. 433 (1880). 



