KIMMERIDGIAN DINOSAURS. 



577 



Other parts of Hind Limb. — Exterior to the right femur and overlain by it is the 

 shaft or slender part of a bone, 1 6 inches in length and 3 inches in breadth ; it bears 

 the proportion of a fil)ula to the tibia above described. -p^^ j 



No recognisable tarsal, or other bone of the hind-foot, has been 

 detected in the indurated matrix forming the bed of the Omosaur. 

 But Professor Phillips, in his instructive ' Geology of Oxford,' 

 states,* " Three metatarsals in the Oxford Museum, apparently of 

 Megalosaurus, lying in their original apposition, have been obtained 

 from the Kimmeridge Clay of Swindon and seem to indicate a 

 tridactyle foot (diagram Ixviii)." I subjoin a copy of the cut of 

 these bones (Fig. 1), deeming it more probable that they belonged 

 to the genus of Dinosaur now known to have left remains in 

 that formation and locality, than to the Mer/alosaurus, of which 

 no indubitable evidence has yet been obtained from Kimmeridge 

 Clay, either at Swindon or elsewhere, a is an outline of the 

 proximal, b of the di.stal, ends. 



These bones exemplify the ' leptopodal ' character of the 

 Dinosaurian foot, due to the reduction of thickness or breadth by 

 suppression of two of the toes, and a consequent departure from the shol-t, thick, or broad 

 ' pachypodal' character of the pentadactyle hind foot of the existing and extinct terrestrial 

 Cheionia and of some Lacertia. 



Metatarsals of Omosaurus ? 



Dermal Spine. — One osseous spine {' Dinosaur ia,' PI, 74, figs. 1 and 2; PI. 75, 

 figs. 2 and 3) has been successfully wrought out of the matrix ; but though a close 

 search was made for other evidences of a dernio-skeleton none have been found. 



The spine in question is 1 foot 6| inches in length, and not more of the tip seems 

 to be wanting than might extend this dimension to 1 foot 7 inches, or, at most, 1 foot 

 8 inches ; the long diameter of its base (PI. 75, fig. 2) is 5 inches ; the shaft gradually 

 tapers to a point. The spine is rounded and slightly compressed ; the narrower diameter 

 is shown in Plate 74, fig. 1, the greater breadth in ib., fig. 2. The surface, smoothest 

 toward the base, becomes slightly broken by fine longitudinal, quasi fibrous, markings ; 

 and this sculpturing becomes coarser as the spine contracts. At every part may be seen 

 small orifices, apparently vascular ; few in number along the basal two thirds, but more 

 frequent near the point. These indicate a periosteum in relation to the supply of a 

 horny sheath, of which we have here the petrified bony core. The texture of the osseous 

 substance is dense (PL 75, fig. 3). 



The base is obliquely truncate, with a boldly sculptured border, broadly and deeply 

 notched as if for strong ligamentous attachments, the whole basal surface being coarsely 

 roughened ; it is also channelled, seemingly, by two vessels entering the substance of the 



* 8vo, 1871, p. 21,-). 



