LOWER LIAS. 
3 
The transverse section of the middle of the shaft is nearly circular ; the 
thickness of the compact wall of the medullary cavity is here about one sixth of the 
transverse diameter of the bone. I have not seen a bone of any other 
Dinosaur indicative of more vigorous action of the hind limbs than the present 
femoral shaft. 
The foregoing interesting and instructive fossil was accompanied by the shaft 
of a tibia of corresponding size, crushed and broken at both ends ; it measured 
18 inches in length and 2 inches 8 lines in diameter at its middle, the circum- 
ference of the shaft there being 10 inches. 
These proportions indicate a hind leg, longer and more slender, relatively to 
the trunk, than in the Megalosaur, Iguanodon, or other Dinosaur with which 
such comparison may be made. The bone being fractured across the middle of 
the shaft, shows a large medullary cavity ; the compact, bony wall does not 
exceed 3 lines in thickness, the cavity itself being 1 inch 3 lines in diameter. 
At the proximal end the antero-posterior expansion and its ridges have been 
broken away. The bone gradually contracts, as it descends, to a subtriedral shaft, 
with a triangular transverse section, two of the angles being rounded off, and 
the third remaining, which was opposite the fibula. The distal expansion has 
been, in like manner, broken away ; but its commencement .shows the rise of an 
anterior ridge in addition to the fibular one. 1 did not think it necessary to 
figure this fossil, as I shortly after received from Mr. Harrison and Mr. Henry 
Morris, F.R.C.S., of Charmouth, the subjects of the two following plates. 
Parts of the Femur, Tihia^ and Fibula forming the Knee-joint. Tab. II. 
In the specimen figured from three views (figs. 1, 2 and 3) in this plate, the 
lower half of the right femur and the upper half of the right tibia and fibula are 
cemented by the matrix in the natural relative position in which they enter into 
the formation of the knee-joint, when bent. This remarkable specimen indicates 
the tranquil state of the sea-bed or bottom after it had received the dead 
carcass of the Dinosaur. No agitation or other external violence has displaced 
the bones of the leg after the solution of the ligaments which tied them 
together in the living animal ; when the depth to which they had sunk, and 
the consistency of the mud or clay bed, tended to retain them in their natural 
position. The portion of femur preserved indicates a slight backward bend of 
the shaft, which at the fractured part — probably a little below the middle of 
the bone — presents an almost circular transverse section. The circumference 
here is 10 inches ; the compact wall of the bone is 6 lines thick ; the medullary 
cavity 2 inches in diameter. A little below the fractured end, and 8 inches above 
