48 
PRIMROSE : THE ANATOMY OF THE ORANG OUTANG 
upon them as additional palmar interossei, and thus described six palmar 
interossei in the Chimpanzee instead of three. From one point of 
view Hepburn would appear to be justified in classing these ventral 
segments of the dorsal interossei with the palmar interossei, and this 
whole group of six muscles, as represented in my Orang, (plate V, figs. 
6 and 7) might be referred to the intermediate layer of Cunningham 
which that author describes as constituting the “ flexores breves.” We 
shall return to the discussion of the interossei after describing the 
muscles of the foot. 
In the dissection of the muscles of the lower extremity one found the 
fascia lata poorly developed, as compared with the similar structure in 
man. 
The Gracilis arose from the body of the pubis by an origin 3.5 cm. 
wide, immediately external to the symphysis and corresponding in 
width of attachment to the depth of the symphysis. It did not extend to 
the descending ramus of the pubis ; it was inserted into the inner aspect 
of the tibia by an expanded aponeurosis of insertion 3 cm. wide. The 
upper limit of the insertion is 3 cm. below the articular surface of the 
tibia. It forms a flat ribbon-like muscle varying in width from 2 cm. 
near its origin to i cm. near its insertion, and was supplied by the 
obturator nerve. Fick remarks on the strong development of this 
muscle in the Orang, and also observed the absence of any origin from 
the pubic ramus. 
The Sartorius, a very poorly developed muscle, arose from the ilium 
below the anterior superior spine, and was inserted into the inner 
surface of the tibia, above and anterior to the insertion of the gracilis. 
This muscle was only about one-fifth the size of the gracilis, and was 
supplied by the anterior crural nerve. On the right side Rudolf found 
that the muscle divided into two tendons of insertion, the anterior being 
inserted into the inner aspect of the tibia in the position indicated above 
for the left side, the posterior joined with the fascia around the knee 
joint. Between these two portions passed an artery of considerable size, 
which was found to arise from the femoral one inch above the knee, and 
run down the inner side of the leg to the cleft between the first and 
second toes, where it disappeared between the heads of the first dorsal 
interosseous muscle; a vein accompanied the artery and entered the 
femoral vein one inch above the knee. Fick^ described an artery, the 
arteria genus suprema, in the Orang as a large vessel as thick as the pro- 
funda arising above the knee and extending with the saphenous nerve 
I Loc. cit. I, p. 35 . 
