56 
PRIMROSE : THE ANATOMY OF THE ORANG OUTANG 
The OMurator internus arose as in man, and passed over the lesser 
sciatic notch, where it is joined by a well-developed Gemellus inferior 
and a less strongly developed Ge 7 nellus superior. The muscle was 
inserted into the upper part of the great trochanter behind the insertion 
of the pyriformis and in contact with the capsule of the hip joint. Fick 
likewise describes the superior gemellus as weak in the Orang, whilst 
Hepburn found them both well developed. Bischoff in the Gorilla 
found the obturator internus completely blended with the quadratus 
femoris. 
The Obturator externus arose as in man and, appearing between the 
obturator internus and quadratus femoris, it found insertion into the 
inner part of the great trochanter just behind the obturator internus. 
The Quadratus femoris was a well-developed muscle. It arose from 
the outer part of the ischial tuberosity by an origin 1.5 cm. wide and 
was inserted into the posterior part of the great trochanter and the shaft 
of the femur below this process. LangeF found the muscle closely 
connected with, and hardly separable from, the adductor magnus,and he 
therefore looked upon it as one of the adductor group. The muscle is 
sometimes blended with the great adductor in man. 
The Semitendinosus arose from the tuberosity of the ischium and the 
bone immediately in front of this by an origin i cm. wide, and was 
inserted into the tibia, the tendon expanding to have a wide attachment 
(2 cm.) into the antero-internal surface of the tibia behind the insertion 
of the gracilis. Rudolf on the right side found a second head of origin 
coming from the ischial ramus and joining the muscle ifz inches from 
its insertion. 
The Biceps arose from the outer part of the tuberosity of the ischium, 
immediately posterior to and slightly in front of the semitendinosus. 
The two were closely associated at their origin. The muscle was 
inserted along the whole length of the lower two-thirds of the shaft of 
the femur, immediately behind the origin of the vastus externus, also 
into the external lateral ligament of the knee joint, the external tubero- 
sity of the tibia, the head of the fibula and into the fascia on the outer 
surface of the upper part of the leg. Associated with this muscle is 
another (the femoral head of the Biceps in man) which arose from the 
shaft of the femur immediately behind {i.e., internal to) the line of the 
femoral insertion of the biceps as described above. The line of origin 
was 4.5 cm. wide. The muscle passed to be inserted into the fascia of 
Loc. cit,, p. 187. 
