Nxwnas.— Notes on the Physiology and Anatomy of the Tuatara. 285 
Muscles of hind limbs. 
Musculus agitator cauds, also called ileoperoneal, very long and thin, 
arises from the sacrum, passing behind the posterior border of the ilium runs 
down the outer and posterior aspect of the leg, and is inserted by a tendinous 
expansion into the outer and upper part of the fibula. In its course 
it covers in the great ischiatie nerve from its escape behind the ilium till it 
pierces the gastrocnemius and soleus. It draws the limb backwards. 
Extensor quadriceps cruris should be called triceps not quadriceps, for it 
arises by three heads. The long head arises from the whole of the outer 
surface of the ilium, occupying the space which in men is occupied by the 
glutei ; it grows bulky and passes down the outside of the thigh to join the 
other heads. The short head arises from the whole of the outside of the 
femur just below the insertion of the M. pectineus. The third head arises 
from the ilio-pubic suture, and near the knee joins the other heads, from 
which it is at first widely separated. The musculus pectineus divides the 
last two heads. The slender head arises close to the origins of the gracilis 
and sartorius. The three heads converge to be inserted by a very broad 
and strong fascia and ligament into the upper surface of the tibia. The 
ilio-pubie head draws the limb forward. 
There is a muscle which Günther calls pectineus, but which Mivart 
and Sanders, in Menopoma, call psoas and iliacus. I think it should be 
called iliacus. Günther calls a wholly different muscle iliacus internus. 
I know not why, for it is an external muscle, corresponding in size to 
gluteus medius. A muscle arises from the inner surface of the cartilaginous 
edge of the uncinate process of the pubis, and passes on over the edge of 
the ilium, to be inserted into the fascia lata, in the same manner as the 
tensor vagine femoris. Below this small muscle is the one which Günther 
pectineus ; it is large and springs from the whole of the ventral surface 
of the pubis and ilium, crosses the ilio-pubie crest, lies close to the aceta- 
bulum, and is inserted by a broad tendon into the middle-third of the outer 
surface of the femur. It also arises from the ilio-pubic ridge. It draws 
the leg forward and rotates it outwards: it is very powerful. This muscle 
and the preceding one are separated from the bladder and cloaca by peri- 
toneum. In somelizards this muscle arises by four heads. In Platydactylus 
japonicus Sanders found the muscle which I have called tensor vagine 
femoris. 
Musculus gracilis arises from the uncinate process of the pubis, anterior 
to origin of the long head of extensor cruris, runs down the inside of thigh 
alongside the head of the biceps, and is inserted into posterior and upper 
part of the tibia. It antagonizes the biceps. 
A broad thick sheet of muscle arises from the symphysis ossium pubis et 
