BY C. W. DE VIS, M.A. 37 
paradoxus azilis 
cm, c.m,. 
Total length........... erbanns 5°65 aes 4°85 
Length of the head ...... 1-4 eee 1:25 
Breadth ,, Oe seev eee 9°3 ees 0°275 
= fof the shaft c.28 075 Sea 0°45 
The facet for the outer condyle is narrower, flatter, and, 
anteriorly, more distinctly separated by a groove from the pre- 
condylar tuberosity. It is also separated from the intercondylar 
area by a narrow and sharp ridge. The inner condylar facet 
(fig. 1, i.c.) is likewise more clearly defined by an extension 
forward of the depression, thus formed into a groove, on the 
inner side of the sunken “spine.” By these inner and outer 
grooves the precondylar tuberosity is narrowed and rendered 
more distinct. The lateral edge of the inner facet which in 
paradoxus is produced into an angle overhanging the base of the 
head, and forming the extreme limit of its breadth, is in the 
fossil shortened and rounded, the head sloping downward and 
outward from it ventrad. The muscular impression on the 
hinder side of the shaft, below the head (fig. 1, m.), is deeper. 
It is bounded on the inner side by a ridge-like margin, and on 
the outer renders the ridge descending from the head much 
thinner than in paradoxus. On the outer side of the anterior 
surface of the shaft, the procnemial fossa or concavity (fig. 2, 
p-) is much longer, reaching downwards quite to the middle of 
. the shaft. The distal end of the shaft is relatively narrower— 
its outer edge, opposed to the inner edge of the fibula, being less 
expanded. It is also more concave on both the facets of its 
hinder side, which are separated more markedly by a low ridge 
descending from about the middle of the shaft. As a conse- 
quence of the elevation of this ridge, and the contraction of the 
outer edge of the shaft, its form is more nearly trihedral than in 
the living species. The inner malleolus (fig. 2, i.m.) is propor- 
tionately smaller, and its summit hemispherical rather than oval. 
The curvature of the shaft is almost as great in the shorter as 
in the longer bone, and is, therefore, absolutely greater. 
