686 



PROF. H. (J. SEELEY ON THE REPTILE 



Femur. 



The proximal fragment of the femur (PI. XXIX. figs. 7, 8), 

 which may have belonged to the same animal as the vertebrae, 

 is 6^ centim. long, exhibits the usual sigmoid flexure, and is 

 compressed on the external or superior surface as in living Cro- 

 codiles. Unfortunately the posterior margin of the head is not 

 quite complete ; but from the region of the great trochanter a 

 powerful muscular ridge, defined by a groove on its anterior side, 

 runs obliquely downward, outward, and forward, exactly as in the 

 living Alligator ; only the muscular power appears here to have been 

 greater. The shaft of the bone is similarly subcylindrical ; and the 

 ridges are distributed in exactly the same way. The inferior surface 

 of the bone shows the articular head to have been rather better de- 

 veloped than in the Alligator, apparently a little broader, and curv- 

 ing a little more inward. The median process is more developed, 

 and extends as a distinct ridge for a short distance down the shaft. 

 The muscular tuberosity which represents the lesser trochanter in 

 Mammals and the trochanter of Dinosaurs generally, seen in the 

 middle of the shaft, is better developed than in the recent type. 

 There is an oblique oval depression with an elevated ridge behind 

 it, and another ridge extending above it proximally. The posterior 

 ridge runs proximally towards the articular head, and is separated 

 from the ridge above the muscle by a groove. Every thing which 

 distinguishes the living Crocodile is here intensified. 



Proximal end of Bight Fibula. 



The specimen which Biinzel regarded (pi. vi. figs. 12, 13) as the rib 

 of a lizard presents all the characters of a small crocodilian fibula, 

 in which, as compared with living forms, the crocodilian attri- 

 butes are somewhat intensified. But the bone-tissue is so dense 

 and brilliant that it has more the aspect of the bone of a bird, Or- 

 nithosaur, or Lacertilian. The fragment (PI. XXVIII. figs. 10, 11) 

 is about 3| centim. long, and has been obliquely fractured below 

 the expanded head, with a minute displacement which slightly aug- 

 ments the curvature of the bone. 



The articular head is relatively thicker than in the Mississippi 

 Alligator, measuring fully 11 millim. from front to back, and 

 7 millim. from side to side. The articular surface is somewhat 

 saddle-shaped as in the living animal, being concave in length and 

 convex in width. It is widened a little posteriorly, owing to the 

 development of an oblique muscular ridge, which in the existing 

 crocodile does not approach so near to the articulation and is less 

 internal. The internal aspect of the bone is less flattened than in 

 the Alligator, is similarly marked below the articulation with short 

 muscular ridges ; but they are not defined by a V-shaped area, and 

 hence the longitudinal tibial ridge, which is well marked proximally, 

 does not originate in a Y-shaped form. The anterior margin of the 

 bone is convex from above downwards ; and there is a corresponding 

 concavity in the length of the posterior outline. The external sur- 



