1869.] HUXLEY—HYPSILOPHODON. 11 
length of the hinder eight of the series of dorsal vertebre. The 
extreme breadth of the distal end is 1-45 inch, the extreme breadth 
of the proximal end, from the inner surface of the articular head to 
the outer surface of the shaft, 1:73 inch. The femur is therefore 
slightly shorter in proportion to the length of the dorsal vertebre 
than in Iguanodon. The faces of the inner trochanter look much 
more directly inwards and outwards, and the whole process has a dif- 
ferent shape from that of Jguanodon. There is no pit above the 
inner trochanter, such as exists in Jguanodon; and the deep inter- 
condyloid groove, on the anterior face of the distal end, which is so 
characteristic of Jguanodon, is wanting. 
The remains of what I take to be the right fibula and tibia are 
seen in front of the pelvis. What remains of the fibula is + inches 
long, and shows the proximal end and moiety of the shaft tolerably 
entire. The former measures 0-7 inch from before backwards, but 
not more than 0-2 inchin width. The anterior edge of the shaft is 
turned towards the eye. An impression on the matrix is continued 
in the line of direction of the bone, and suggests that it was alto- 
gether about five inches long, and that its distal end had a width 
of 0-4 inch. In Jguanodon, the length of the tibia is to that of the 
femur as 31 to 33, and the fibula is somewhat shorter than the 
tibia. If Hypsilophodon followed the proportion of Jquanodon, the 
tibia should be 5:35 inches long, and the fibula rather more than 
five inches. 
On reference to the memoir which I have cited, it will be ob- 
served that my interpretation of the bones described is very dif- 
ferent from that adopted by Prof. Owen (p. 2). He terms the 
femur (65) “the right femur,” and states that “the bones of the 
right hind leg are almost completed when the blocks containing 
their opposite ends are brought into juxtaposition.” But the most 
cursory inspection is sufficient to show that the femur belongs to 
the left side, and, as I have proved, the so-called right tibia and 
fibula (66 and 67) are really the two ischia and the pubes. 
I find myself compelled to dissent as widely from Prof. Owen’s 
view of what he terms “ the principal bones of the right hind foot.” 
I have no sort of doubt it is the left hind foot. For there are two 
bones belonging to the distal tarsal series in their natural relation 
with one another, and with two, if not three, metatarsal bones. 
These bones are obviously the homologues of those which exist in 
Scelidosaurus and in the Crocodilia, and which lie on the outer side 
of the foot. The metatarsals which are connected with these bones, 
therefore, must needs belong to the outer, or fibular, digits ; and, as 
the dorsal surface of the metatarsus is turned towards the eye, the foot 
can only be that of the left limb. In the proximal row of the tarsus 
lie a caleaneum (which seems to have a process as in Crocodiles) and 
an astragalus, with a convex distal face and seemingly flattened from 
above downwards. Whether it has an ascending process cannot be 
distinctly made out. The proximal and the distal series of bones 
~ are dislocated, and what looks like the end of the tibia is seen be- 
tween and below them. The metatarsals of the first, second, and 
