234 Transactions of the South African Philosophical Society. 
The fibula is unfortunately broken at its lower end, but otherwise 
is perfect. It is a moderately stout bone, with the lower end 
apparently only slightly enlarged, but with the upper end much 
flattened and very greatly expanded. The upper end has articulated 
with the tibia and probably also with the femur by its inner angle, 
while the outer part of the upper expanded portion extends con- 
siderably above the articular surface. In the large majority of 
mammals and reptiles the upper end of the fibula is comparatively 
small, and in the higher mammals it only articulates with the tibia. 
In the Marsupials and the Monotremes the fibula usually has an 
expanded head and articulates with the femur as well as with the 
tibia. In Dasywrus the fibula is but little expanded at its upper end, 
but in the nearly allied Didelphys the expansion is considerable, and 
in some Marsupials the expansion is very great. The greatest degree 
of expansion I have observed is in the large flying Phalanger 
(Petauroides volans) (Fig. 3). In both the Monotremes the ex- 
pansion is well marked, and in Ornithorhynchus is very peculiarly 
developed. In Oudenodon and Dicynodon there is some degree of 
expansion of the upper end of the fibula, but it is less marked than 
in Ptychosiagun. 
The two toes were found lying side by side and one has been 
cleared so as to show the under surface, the other the upper. Of 
the one the metatarsal and two phalanges were found; of the other 
the three phalanges. Fig. 10 Pl. xxxii. represents the upper 
surface of what is probably the third toe of the left foot. Fig. 6 
shows the under surface of what is probably the fourth toe of the 
same foot. 
The metatarsal bone is an irregular rhomboidal bone almost as 
broad as it is long. Hach side and the under surface are considerably 
hollowed out, while the upper surface is only slightly concave. The 
articular surfaces, like that of the lower end of the tibia, have been 
padded with cartilage. The first phalanx in both the third and 
fourth toes is a very short but broad bone, being about twice as 
broad as it is long. It apparently to a slight extent overlaps the 
second phalanx. The second phalanx is about as long as it 1s 
broad. Its distal end has a well-marked articular head for the 
ungual phalanx. The ungual phalanx is well preserved in the 
third toe. It is a broad, flattened bone, which is only slightly 
curved. It must have supported a large and powerful claw, 
though a moderately flat one. The general proportions of the 
bones of the toes are closely paralleled by those in some of the 
toes of Hclidna. Fig. 8 represents the second toe of the right 
foot of Hchidna and shows a similar shortening of the first phalanx ~ 
