OOLITIC DINOSAURS. 577 



core in Iguanodon is shorter in proportion to its basal breadth than is the problematical 

 spine in Omosaurus. 



It is significant of the nature of this one unsymmetrical osseous spine that the bones 

 of one of the fore limbs, the left, and that limb only, should have been preserved, and in a 

 more complete state than any other part or limb of the present remarkable Dinosaurian 

 framework ; the spine in question lay not far from the radius and carpus. 



Two spines of similar form to that of Omosaurus, but of larger size, were discovered 

 near each other in a pit of Kimmeridge clay at Wootton Bassett, Wiltshire, and 

 formed part of the well-known collection of William Cunnington, Esq., F.G.S., now in 

 the British Museum. Whatever contiguous bones may have been dug out of the same 

 part of the pit were not preserved. These two spines form a pair, and resemble each 

 other as much as would the right and left radius, or the right and left ulna, of the same 

 Dinosaur? They differ from the (carpal ?) spines of Omosaurus in having a sharp edge, 

 which in a transverse section, like that of fig. 4, PI. 77, would terminate one end of the 

 long diameter of the ellipse. The lethal power of the weapon was augmented by this 

 character of the sword added to that of the pike. The degree of obliquity, the coarse 

 marginal notching, and vascular perforations of the base, are as in Omosaurus ; but the 

 expansion is greater, yielding dimensions of 8 inches and Q\ inches in long and short 

 diameters ; thei'e is a slight submedial ridge dividing the basal articular surface into two 

 shallow channels. The long diameter of the shaft, four inches beyond the least produced 

 part of the base, is 3^ inches, being nearly the same as in Omosaurus. The edge of the 

 spine is along the same line as the most produced part of the base. The shaft has a 

 central cavity, as in Omosaurus. Should these prove to be a pair of carpal spines they 

 indicate a species of Dinosaur distinct from Omosaurus armatus. They will be further 

 described and figured in a subsequent part of the present work. 



Order DINOSAURIA. 

 Genus — Cetiosaurus.* 



Species — Cetiosaurus loiir/us, Ow. (Plate 76, and Woodcuts 3 — 11). 



Until a comparatively recent period the generic or family characters of the great 

 extinct Cetiosauroid Reptiles were founded on a few scattered bones of the trunk and 

 limbs. t The texture of these fossils mainly differentiated them from the corresponding 

 vertebrae and limb-bones of previously determined genera or species of Saurians. No 



* Gr. K»)reios, cetaceous ; aaiipos, Lizard ; " Report on British Fossil Reptiles," Part ii, in ' Reports of 

 the British Association,' &c., for the year 1841 ; also ' Proceedings of the Geological Society of London' 

 or June, 1841 (vol. iii, p. 4,57). 



t Ante, p. 40.V ; provisionally referred to the order Crocodilia. 



