383

353

ridge (ib. q) commencing at the inner side of the shaft, one inch below the neck. The
two oblique ridges are divided by a smooth interspace 4 lines in breadth, below
which is the orifice of the medullary artery (ib. r). On each side of this orifice the
lineae asperae are, as it were, resumed, and decend slightly diverging, -- the outer one
(ib. p') gradually subsiding near the ectocondylar pit (k) ; the inner one (ib. q) descends
an inch and a half below the arterial orifice to form the tuberosity, q'. Internal to
this rises a second rough tuberosity (ib q"), continued by a ridge to within an inch of the
hind angle of the inner condyle (ib. u).

From the ectotrochanterian tuberosity (Pl. XLI. fig. 1, l) the strong ridge bisecting
the fore part of the mid third of the shaft is continued down near the mid line of that
surface. Six inches below the upper end of the femur this ridge, which divided the
attachments of the "vastus externus" and "vastus internus" muscles, bifurcates, its
divisions diverging to the upper end of the condylar risings (ib. u, y), but subsiding
before attaining these.

At the lower part of the pretrochanterian surface, midway between the head and the
ectotrochanterian tuberosity, is the rough surface, partly prominent, partly depressed
(Plate XLI. fig. 1, s), which seems to represent the small trochanter in Mammals.

The rotular cavity or channel (ib. fig. 1, t), 2 inches across and 1 1/4 inch in depth,
shows no trace of the rising marked in that part of the femur of Dinornis giganteus 1.
The anterior intercondylar ridge dividing the rotular fossa is partially divided into
two depressions, the inner one (ib. v) being the deepest, the outer one (v') the largest.
These are divided from the popliteal cavity (Pl. XLI. A. fig. 1, z) by the post-intercon-
dylar ridge (ib. w), which is well marked, but shorter ,thicker, and more rounded than
the anterior one (Pl. XLI. fig. 2, t').

The entocondylar articular surface (ib. u') had the usual relative size and shape 2.

The ectocondylar surface for the tibia (ib. x) is comparatively small, measuring
1 inch 9 lines by 1 inch in extent ; it is continued over the ridge-like posterior Pro-
jection of this part of the condyle to that on the concavity or groove for the head of
the fibula (Pl. XLI. A. fig. 1, y), which groove is feebly divided into an upper (y') and
lower (y") tract.

The popliteal space (ib. fig. 1, z) has the usual dinornithic depth, shape, size, and
oblique direction. It is rugous ; and some small foramina at it s deepest part are the
sole representatives of a pneumatic system, though probably related only to the trans-
mission of vessels.

The contrast is striking, in placing by the side of the above-described bone the femur
of any of the species of large existing Struthious birds, in regard to every indication of
the strength and vigour of application of the hind limbs. The chief results of the
comparison of the femur of Dinornis with that of Struthio were recorded in the Memoir

1 Pl. XXXVI. fig. 2, r 2 Pl. XXXVIII. fig. 3, t (Dinornis casuarinus).