/ 
52 PRIMROSE : THE ANATOMY OF THE ORANG OUTANG 
diminutive size of the nates in apes, which is usually ascribed to the 
ill-developed glutei muscles, was not demonstrated in my specimen. Fick 
also^ observed that the gluteus maximus, though relatively weak, was 
still a strong muscle in his Orang, its weight being 432 grms. whilst the 
gluteus maximus in a lean man was found by Langer to be 366 grms. 
The Gluteus 7 nedius (Plate VI., fig. 8) was a large well developed 
muscle, which arose from the dorsal surface of the ilium as far forwards 
as the anterior superior spine, and backwards over the whole extent of 
the iliac crest, and from the dorsal surface of the ilium below this, some 
fibres coming from the posterior sacro-iliac ligament. Along its pos- 
terior border it is joined by the pyriformis muscle. 
The Pyriformis is a narrow ribbon-like muscle arising from the 
anterior surface of the sacrum. It joins the gluteus medius on its deep 
aspect and proceeds to its insertion into the upper part of the great tro- 
chanter, as in man. It was intimately connected with the gluteus medius, 
but it was possible to separate them entirely from one another. It is 
customary, according to Bischoff, to find these two muscles closely con- 
nected in apes. Hepburn found them blended in all four anthropoids. 
The muscle is present in all apes. 
The Gluteus minimus (Plate VI., fig. 8, g.min.) arose from the margin 
of the great sacro-sciatic foramen, and slightly from the dorsal surface 
of the ilium below this by an origin 2.5 cm. wide; it passed outwards 
beneath the pyriformis and the gluteus medius and was inserted into 
the anterior margin of the great trochanter. 
The Scansorius (Plate VI., fig. 8, scan.) arose from the anterior 
margin of the ilium below the anterior superior spine by a broad base 
of origin 3.5 cm. wide, the muscle being triangular in shape. It was 
inserted by its apex into the anterior border of the great trochanter by 
an insertion 1.5 cm. wide immediately in front of the gluteus medius 
and is embraced at its insertion by the vastus externus. This well- 
developed muscle lay at its origin between the gluteus medius behind 
and the iliacus in front. The narrow ill-developed sartorius separates 
the iliacus from the scansorius, whilst the rectus also separates these two 
muscles along the inner border of the scansorius. The muscle was very 
distinct and separate from both the gluteus medius and the gluteus 
minimus. 
The scansorius is described by Fick as atypical Orang muscle. It is 
certainly best developed as a separate muscle in the Orang, whilst in 
the other apes (both anthropoid and lower apes) it is more or less 
I Loc. cit. I, p. 36. 
