526 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [June 25, 



The general form and the facies of the cylindrical teeth of Hypsi- 

 lophodon are so like those hitherto generally regarded as Hylaeo- 

 saurian that I cannot help suspecting that these reputed Hylaeo- 

 saurian teeth may really be the as yet unknown premaxillaries of 

 MantelPs Iguanodon ; and the suspicion derives strength from the 

 fact that these teeth are not very rare in those Isle-of- Wight 

 Wealden beds which also yield Iguanodon remains, whilst other 

 indisputable remains of Hylaeosaurians are extremely infrequent 

 anywhere in the island Wealden formation. 



Vertebral Column. — All the vertebrae were crushed and mutilated 

 beyond reparation. A few centra which I recovered show that 

 both articular surfaces are nearly plane ; or else the periphery is 

 plane or gently swollen, and the middle is very slightly hollowed. 

 The outer or non-articular surface is smooth. The sides are scarcely 

 convex vertically, and slightly concave horizontally. In all the ver- 

 tebrae the neurepophysial suture persists, as Prof. Owen found in 

 the Mantell-Bowerbank skeleton ; and the neurapophysis had, in 

 most instances, separated from the centrum. The neural canal, in 

 the neck-vertebrae, is very capacious ; and the spinous processes are 

 dwarfed here. The neural surface of the centrum has a narrow 

 longitudinal median groove not covered by the neurapophyses, a fact 

 mentioned by Prof. Owen. In some centra this groove has the form of 

 a deep cleft, which sinks below the level of the middle of the centrum. 

 Two centra from, I think, a little in advance of the sacrum are 

 respectively -7 and '65 inch long, and -4 inch in their vertical dia- 

 meter. A mutilated sacrum of an older individual consisted of four 

 anchylosed centra, with a small remnant of a fifth. 



Hibs. — Associated with the vertebral column of the base of the neck 

 and front of the chest were many fragments of double-headed ribs. 



Shoulder-girdle and fore limb. — The scapula, coracoid, and left 

 humerus I found lying close together ; and near these, in other blocks 

 of clay (for the cliff was very fissured), was a forearm with its 

 manus, and a flat bone, presumably the sternum. 



The scapula (fig. 2, a) is a long thin slightly recurved blade, a little 

 expanded at the vertebral end, and widening considerably towards its 

 articular extremity. Its anterior margin, in the middle two thirds, 

 is nearly straight ; towards the ventral end it bends forwards and 

 includes an acute angle with the coracoid border, whilst dorsally it 

 curves backwards. The expansion of its dorsal and ventral ends 

 renders the posterior border concave. The articular border is di- 

 vided into two facets, of which one is longer, straight, anterior, for 

 union with the coracoid ; and the other, shorter, stouter, and poste- 

 rior, forms half of the glenoid fossa (fig. 2, b). These two facets, in 

 my specimen, include an angle of about 125°. A larger scapula, of 

 a probably mature individual, had a longer and narrower blade, and 

 what seemed to me a short precoracoid process. 



Compared with the scapulas of other Dinosauria, that of Hypsilo- 

 phodon (particularly when fully grown) resembles that of Iguanodon 

 Mantelli in the length and narrowness of the blade, and, unless ap- 

 pearances have misled me, in the presence of the precoracoid pro- 



