38 ME. R. LTDEKKER ON DINOSAURS OF THE "SVEALDEN 



Jguanodon Daivsoni was a species intermediate in size between 

 I. hernissartensis and /. Mantelli, the middle dorsal vertebrae * 

 having but slightly compressed centra, with the rib-facet rising to 

 the level of the neural platform. The ilium, of which a greatly 

 reduced representation is given in tig. 1 B, is characterized by its 

 great vertical depth, and the absence of that reflection of the supe- 

 rior border which is so marked in /. bernissartensis (fig. 1 A) and 

 /. Mantelli (fig. 1 D) ; and also by the contour of its postacetabular 

 portion, which forms a long and deep plate with a rounded termi- 

 nation, in which there is only a very slight inflection of the inferior 

 moiety. Equally characteristic is its preacetabular process, which 

 is long and comparatively shallow, with a broad horizontal roof-like 

 inward extension at its point of origin from the preacetabular notch, 

 and an outward inclination of its lower border as it approaches 

 the extremity. The pubic process is mainly directed forwards. An 

 imperfect skeleton in the British Museum (No. E. 1627) from the 

 Wadhurst Clay of Brede, near Hastings, may be referred to this 

 species, since the portion of the right ilium which now remains 

 agrees exactly with the type specimen. The femur of this skeleton 

 has a length of about 37 inches, and the head placed approximately 

 at right angles to the shaft ; but the form of the inner trochanter 

 cannot be determined owing to the imperfection of this part of the 

 bone. 



Having now indicated the chief characters of Iguanodon Dawsoni, 

 we may proceed to notice the chief specimens of the other forms 

 from the same deposits. 



Iguanodon Fittoni t. — The type specimen of this species is the 

 ilium represented in fig. 1 C (B.M. No. R. 1635), which was ob- 

 tained from Shornden Quarry near Hastings, from a three-foot bed 

 of ferruginous sand, which is separated by a stone band of two feet 

 in thickness from the underlying clay bed, four feet thick, which 

 jdelded the type specimens of /. Daiusoni. At a distance of some 

 25 yards to the westward in the same stratum an imperfect caudal 

 vertebra and the proximal extremity of a left ischium were obtained ; 

 while 25 yards still more to the west was found the undermentioned 

 sacrum, also in the same bed. It might be considered that an in- 

 terval of 50 yards between two specimens would show that they 

 were not referable to the same individual. In this case, however, 

 no other bones have been found in the same part of the quarry, and 

 the position of the ischium serves to connect the ilium with the 

 sacrum. Moreover all these bones belong to the same region of the 

 body, while the ischium and ilium are both of the left side. That 

 different bones of a single individual in these deposits do become 

 widely separated horizontally is proved by the metatarsals of Mega- 

 losaurus described in the second section of this paper, one of which 

 was obtained in 1884, while the other was found in 1889 at a 

 distance of about 180 yards from the spot where the first occurred. 

 It seems, therefore, to be most probable that the four above-men- 



* Quart. Joiirn. Geol. Soc. vol. xliv, p. 48, fig. 1. 

 t Geol. Mag. decade 3, vol. \i. p. 354. 



