WEALDEN IGXJANODONT AND OTHER DINOSAURS. 51 



knowledge of the pelvis of the latter, the closeness of its relationship 

 cannot be determined. Its higher geological horizon renders it, 

 however, pretty certain that it cannot be specifically the same as 

 the latter. In the structure of the pelvis this Iguanodont approxi- 

 mates to Camptosaurus and Hypsilophodon, and it also agrees with 

 the former in its sacral characters ; its hind foot was, however, 

 essentially that of Iguanodon, and the presumption therefore is that 

 the manus was also of similar structure. In the opinion of many 

 authorities I have little doubt that these differences would bo re- 

 garded as of generic value, and the question would then arise 

 whether this form should constitute a new genus, or whether it 

 should be classed with /. Prestwichi as a species of Cumnoria, or 

 possibly with S. gracilis as a Splienospondylus. I am, however, 

 inclined to the opinion that it is preferable, at least for the present, 

 to employ the generic term Iguanodon in a sense which will embrace 

 all the variations between the typical and the present form, and I 

 accordingly propose to include the latter in that genus, under the 

 name of Iguanodon Dawsoni. 



In this sense the genus Iguanodon may be divided into a Eu- 

 iguanodont group comprising 1. Mantelli and 1. bernissartensis, and 

 characterized by the pointed posterior extremity of the ilium, the 

 short pubis, the twisted ischium, and the compressed sacrals, as well 

 as by certain features of the anterior dorsal vertebraD ; and into a 

 Proiguanodont group, including 7. Prestwichi and I. Daiusoni, and 

 characterized by the blunt extremity of the ilium, the probably 

 long pubis, the absence of twist in the ischium, and the hgemally 

 flattened sacrum. The Proiguanodont group will be the one con- 

 necting the typical forms of the genus with HypsUophodon and 

 Camptosaurus. 



I may here call attention to certain specimens some of which 

 may probably belong to the Wadhurst-Clay Iguanodon. The first 

 is a fine left scapula (No. E,. 966) obtained by Mr. Dawson from the 

 Wadhurst Clay, which agrees in relative size with the type ilium. 

 This bone is remarkable for having a conical puncture on the 

 posterior side on the middle of the dorsal surface, which appears to 

 have been not improbably caused by a wound from the strong spike 

 terminating the pollex of another, and probably male, individual. 

 It may also be observed that on the anterior border of the proximal 

 expansion there occurs a facet, which I at first thought might 

 indicate the articulation of a clavicle; but Prof. Seeley, to whom I 

 pointed it out, suggests that it may merely indicate a cartilaginous 

 epiphysis *. 



Among the Fox Collection from the Isle of Wight, I find the 

 centrum of a posterior dorsal or lumbar vertebra (No. R. 136) from 

 the Upper Wealden, which, from its precise resemblance to the 

 hinder trunk vertebrae of /. Paivsoni, I refer provisionally to that 

 species. If this should prove the existence of that form in the 



* It may be observed that in the ' Geol. Mag.' 1887, p. 85, Prof. Seeley 

 states that the absence of such a facet is one of bis reasons for rejecting 

 Mr. Hnlke's interpretation of the sternal ossifications. 



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