WEALDEN FORMATIONS. 19 



greater relative slenderness and its better developed processes, especially the inner, 

 or entocnemial, ridge. The differences are of that degree which might be expected 

 to be found in a limb-bone of another species or genus of large Dinosaurian reptile ; 

 and no reptile answering to that character has yet been determined, by fossil remains 

 from the Stonesfield Oolitic slate, except the Megalosaurus. The modifications in 

 question are such, moreover, as accord with the superior energy and activity which a 

 carnivorous reptile like the Megalosaurus might be expected to possess in contrast 

 with the heavier and more bulky herbivorous Iguanodon. There can be no reasonable 

 doubt, therefore, that we have, in the subject of T. IX, the veritable leg-bone or 

 tibia of the Megalosaurus. 



Portions of metatarsal bones, most probably from their size and texture, those of 

 the Megalosaurus, have been obtained from the Stonesfield Oolite and Sussex 

 Wealden : one of these is figured by Dr. Buckland in PI. xlix, fig. 6, of the volume of 

 the ' Geological Transactions' containing his original Memoir on the Megalosaurus. 



These fossils, however, which I have examined in the Geological Museum at 

 Oxford, do not present sufficiently marked characteristic modifications to render a 

 special description of them serviceable for the identification of future specimens of 

 Megalosauri. 



Ungual Phalanges. Tab. X. 



Both teeth and vertebrae of the Megalosaurus have been discovered in the Wealden 

 strata which contain remains of the Iguanodon and other large reptiles. Besides the 

 claw-bones which, from their broad, obtuse, massive and slightly curved shape, I have 

 referred to the herbivorous Iguanodon, there have been obtained, also from the 

 Wealden, claw-bones which, by their sub-compressed, curved, and sharp-pointed 

 shape indicate a carnivorous reptile ; and some of these, by their size, might well belong 

 to the Megalosaurus. 



Without, however, the association of such claw-bones with other parts of the limb, 

 recognisably Megalosaurian, a certain conclusion of their nature cannot be arrived at. 

 The probability, however, of this latter type of ungual phalanx being that which the 

 Megalosaurus would exhibit, decides me to give the requisite illustrations of it in the 

 present Monograph. 



T. X, figs. 1 and 2, give side views of an ungual phalanx, wanting the tip, and 

 with a portion of matrix attached to the base. The length of this phalanx, if the point 

 be restored according to the pattern of the smaller and better preserved specimen of 

 the same kind, fig. 5, would be between 5 and 6 inches : the depth of the base of the 

 phalanx is 2 inches 9 lines ; the extreme breadth of the base being but 1 inch 5 lines. 



