MUSCULATURE. 207 
What is clearly the gluteus medius (Plate 1, fig. 1, gme) is present in much 
the usual relations. It is a large muscle-mass arising from the lateral face of 
the ilium, and from fascia connecting the spines of the last lumbar and first 
two sacral vertebrae. It inserts on the head of the femur from the great tro- 
chanter to the acetabulum. What seems also to be a division of this muscle 
arises from the lateral part of the tuberosity of the ium and passes as a rather 
easily separable bundle to an insertion about 10 mm. long at the proximal 
end of the trochanteric ridge. The muscle here considered the gluteus medius, 
Mivart and Westling have taken to be the minimus, since they assigned to the 
medius the crural division of the maximus. The minimus is, however, wanting 
as a distinct muscle in both the Echidna and the Proechidna. 
The pyriformis (Plate 1, fig. 1, py) seems to be represented by a small muscle 
from the tips of the transverse processes of the fourth sacral and first caudal 
vertebrae. It passes over the posterior tuberosity of the femoral head and 
inserts on the lateral side of the trochanteric ridge at slightly less than half 
its length, just caudal to the insertion of the gluteus maximus. Between the 
latter and the pyriformis issues the sciatic nerve. Mivart found a similar 
muscle in the Echidna arising from five caudal vertebrae, but Westling failed 
to find it. Mivart notes that the nerve is superficial to the muscle instead 
of beneath it as usually. 
The capsularis shows the usual relations. It arises as a thin sheet from the 
ilium between the acetabulum and the origin of rectus femoris and spreads out to 
an insertion about 10 mm. long at the proximal portion of the trochanteric ridge. 
The quadratus femoris is a large muscle from a triangular origin extending 
from the tuberosity of the ischium to the acetabulum. It is inserted by tendi- 
nous fibers on the great trochanter just distal to the insertion of the gluteus 
medius and for about 10 mm. along the trochanteric ridge. Mivart speaks 
of this as a “delicate”? muscle in the Echidna. 
The obturator externus appears to be much as in the Echidna. It is large, 
of a triangular outline, and lies as usual underneath the adductor femoris. It 
originates from the anterior edge of the pubis at the base of the epipubic bones, 
and thence along the entire pubic symphysis and for about 15 mm. on the ramus 
of the ischium.- At the most anterior portion the origin extends from the pubic 
border to the lip of the obturator foramen, but elsewhere it is from the outer 
edge of the pubis and ischium, whence it tapers slightly to the insertion in the 
entire intertrochanteric fossa. 
The obturator internus is wanting as in the Echidna. 
