HADROSAURUS. : 95 
As in the case of the femur, in comparing the tibia of Hadrosawrus with that of 
Cyclura, ete., we are struck with an apparent reversal of many of the anatomical 
characters. Thus in the former the bone is longest externally, in the latter inter- 
nally; in Hadrosaurus the long diameters of the head and tarsal extremity are 
opposed ; in Cyclura they are parallel. 
The fibula, represented in Figs. 7, 8, Plate X VI, from the left side, has lost its 
upper fourth, and in its present condition measures twenty-eight inches in length. 
At the broken extremity it is trilateral; and it gradually expands in a flattened, 
clavate manner to the lower extremity. Externally, Fig. 7, the bone is transversely 
convex, and for the greater part of its extent internally is concave in the same 
direction. The tarsal articular surface, Fig. 8, is bent ellipsoidal in outline, and 
is convex and ronghened. At the broken end the specimen measures one inch ten 
lines in diameter; the tarsal extremity is five inches and a quarter wide, and two 
inches and one-third in thickness. 
The fibula of Hadrosawrus bears a near resemblance to that of Jywanodon, as 
represented in Prof. Owen’s Figs. 3, 4, Plate XX, of the British Fossil Reptiles, 
Dinosauria. 
The two bones, represented in Figs. 7-10, Plate XIV, from their proportions are 
supposed to belong to the metatarsus, and like the bones of the leg above described 
probably appertain to the left side. 
The large specimen (Figs. 7, 8) has a cylindroid shaft, compressed from above 
downwards and moderately expanding towards the extremities. The tarsal ex- 
tremity is trilateral, flattened below, convex above, and presents a triangular con- 
cave surface on its inner side. The tarsal articular surface is vertically crescentic 
in outline and moderately concave. The phalangial extremity is quadrate, deeply 
impressed at the sides for the attachment of lateral ligaments, convex above, and 
deeply notched below. Its articular surface is vertically convex, slightly depressed 
towards the middle inferiorly, and extends upon a pair of prominent condyles below. 
The measurements of the bone are as follows :— 
Inches. Lines. 
Extreme length . ; - : : ; ‘ 3 : ep aly. 8 
Length at its upper part . c C 5 - - > ‘ sulk 3 
Breadth of shaft at middle. : : : : : LO 3 
Depth of shaft at middle 1 9 
Depth of tarsal extremity internally! 4 6 
Breadth of tarsal extremity at middle 3 1 
Height of phalangial extremity from a level 4 2 
Breadth of phalangial extremity above and below 4 2 
The second specimen (Figs. 9, 10), suspected to belong* to the inner toe, has the 
shaft cylindroid, but much compressed obliquely from within outwardly and above 
downward. The extremities are broadly expanded and oblique in their position. 
The tarsal extremity is more than twice the height of its breadth, and presents a 
long elliptical articular surface, moderately concave at its upper two-thirds and 
convex at its lower third. The phalangial extremity appears rhombohedral in out- 
line with concave sides. Its articular surface is vertically convex and depressed 
towards the median line. 
