1886. ] GEOCOCCYX CALIFORNIANUS. 475 
of the muscle, which latter must be cut across and reflected in order to 
discover them. From this origin the peroneus longus as a rather thick, 
coneavo-convex muscle passes down in front of the leg, its outer edge 
dipping down for attachment between the tibialis anticus muscle, 
which it almost completely covers, and the flexors to its outer side ; 
its inner edge is free and thin, and overlaps the gastrocnemius. 
Low down on the outer side of the tibial shaft the fibres of the 
peroneus longus have converged to terminate in a small narrow tendon, 
This tendon, just above the condyles of the tibia, bifurcates, the short 
slip of the bifurcation going to the fascia covering the block of 
cartilage (which I have termed the tibial cartilage) at the back of 
the tibio-tarsal joint for attachment, while the longer slip passes 
across the articulation to the bundle of tendons at the back of the 
tarso-metatarsus to merge with one of the special flexors. 
Removing this superficial layer of muscles of the pelvic limb and 
turning our attention once more to the thigh, the following ones are 
presented to our view for examination :— 
The gluteus medius muscle (Plate XLIV. fig. 2, gl.m) is found 
to be strong and tendinous. It, as in all of the birds that I have 
examined, fills the concavity of the preacetabular portion of the 
pelvis, and here in Geococcy# extends laterally much beyond the bone, 
as this bird has a very narrow pelvis anteriorly, while it demands 
the use of a powerful set of gluteal muscles. 
The gluteus medius arises by a strong, flat tendon from the superior 
surface of the outer moiety of the anterior iliac margin, by a dense 
fascia from the entire line bounding the preacetabular concavity, 
and finally by fleshy fibres from the upperside of the ilium itself. 
The fibres of the roundish muscle thus formed converge as they pass 
to the caput femoris, and, just before arriving at the bone, they 
terminate in a dense flat tendon, which, passing over a bursa, is 
inserted at a point on the antero-external aspect of the femoral 
trochanter. 
The gluteus minimus (Plate XLIV. fig. 2, g/.min) is a very much 
smaller muscle than the gluteus medius, and is found immediately 
beneath it to its outer side. In form it is oblong, and fully three 
times as long as wide. It arises from the outer superior surface 
of the fore part of the ilium, and passing obliquely downwards 
and backwards as a flat narrow band of fibres, it becomes inserted 
by semitendinous ones on the outer aspect of the upper third of the 
femur, just below the trochanter. This muscle may also ride over 
a small bursa, just before it arrives at its insertion. 
The extensor femoris is readily divisible at its lower half into two 
parts, the bulkier anterior one representing the erureus (Plate XLIV. 
fig. 2, c), and the posterior division the vastus externus (Plate XLIV. 
fig. 2, V.£). 
As awhole, this powerful extensor of the leg upon the thigh 
arises from the antero-external aspect of nearly the entire length of 
the shaft of the femur, and from a portion of the trochanter at its 
summit. At about its lower fourth it terminates in a broad tendinous 
expansion, which, as has already been described, is amply reinforced 
by other insertional portions of the superficial muscles of the thigh. 
