Mackintosh — On the Myology of the Genus Bracli/piis. 525 
two foremost caudals, and inserted into the outer and anterior part 
of the great trochanter." Gluteus medius and pyriformis are repre- 
sented as distinct by Cuvier. 
Obturator internus ('04) is moderate in Arctopithecus, small in B. 
tridactylus (Professor Macalister), if present at all fused with gemelli 
and quadratus femoris (Professor Humphry). It is displaced on 
account of the position of the lesser sciatic notch, and is really a 
gemellus arising from the descending ramus of the pubis. 
Obturator externus (-15) is double, one part from the horizontal rim 
of the pubis, above the obturator vessels, the other as usual from the 
obturator membrane ; the insertion is femoral as usual. It was single 
and normal in E. tridactylus. 
Gemelli both present, and equal in size, united to form a single 
muscle in Professor Humphry's specimen. 
Quadratus femoris (-04) normal, and well developed (Arctopi- 
thecus), small (Professor Macalister), if present at all united with the 
gemelli (Professor Humphry). 
Quadratus lumborum in Arctopithecus arises from the sides of the 
bodies of the three upper lumbar vertebrae, and is inserted into the 
transverse processes of the three posterior ones, and into the iliac crest. 
It is not described in B. tridactylus. 
Iliopsoas (-33) has the usual origin, and is inserted into the 
lesser trochanter, and about one inch of the femur below that process. 
Psoas magnus and iliacus seem to have been distinct in Professor 
Humphry's specimen. 
Psoas parvus (*07) feeble in all, takes origin from the bodies of the 
two upper lumbar vertebrse, and has the usual insertion. 
Levator caudse takes origin external to longissimus dorsi from the 
widely expanded transverse processes of the sacral vertebrse, and is 
inserted into the laminae of the caudals, one tendon going to each. 
Sartorius ('10) arises partly from the anterior superior spine of the - 
ilium, but chiefly from the outer portion of Poupart's ligament, and 
has a double insertion, one tibial as usual, the other into the inner con- 
dyle of the femur and capsule of the knee joint. Professor Macalister 
only found the former insertion, and Professor Humphry describes 
the fibres of this muscle at its origin (iliac spine) as being apparently 
somewhat continuous with those of the external oblique and its 
insertion to be into the lower internal aspect of the femur, as well as 
into the upper part of the tibia. 
Pectineus ('08) has the usual pectineal origin, and is inserted into 
the lower half of the femur. Professor Macalister found this muscle 
to consist of two parts, "arising from the pectineal ridge on the os 
innorainatum, and inserted into the femur for the entire length ; the 
long superficial portion passes internal and nearly parallel to the sar- 
torius, while the deeper part seems to be the true pectineus." 
Gracilis ('26) is an enormous muscle arising from the horizontal 
ramus of the pubis for a distance of half an inch external to the 
symphysis, and extending outwards from this over the acetabulum to 
