1870. ] MYOLOGY OF CHAMELEON PARSONII. 879 
The quadratus femoris (fig. 22, Q) arises from the postero-superior 
side of the tuberosity of the ischium, and is inserted into the summit 
of the head of the femur, above the great trochanter, but more in 
front (i. e. on the extensor aspect) of the femur. 
Obturator externus (fig. 21, O). This muscle arises from the 
outer surface of the ischium, and is conterminous with the quadratus 
femoris. It is inserted all along the great trochanter, on the inner 
side of the femoro-caudal. 
Fig. 22. 

Inner side of right half of pelvis. 
D°, Gluteus secundus. J', 2*, 73. Tiacus. 0.1. Obturator internus. 
@. Quadratus femoris. 
Obturator internus (fig. 22, O. I). This muscle arises inside the 
pubis, conterminous with the inner margin of the origin of the third 
part of the iliacus. Passing downward (through the obturator 
foramen, and thus becoming superficial to the second part of the 
iliacus), it is inserted into the femur along its posterior side down to 
the summit of the insertion of the adductor. 
Rectus femoris (figs. 2,4, 17, 18, 19, & 21, F', F’, & F’). Three 
distinct muscular parts seem to belong to the category to which the 
rectus femoris of Mammals belongs. One of these parts seems to 
represent that which I have called rectus femoris in the Iguana*, 
and the other two parts to answer to what I have called gluteus 
maximus in the. Iguanart. 
The first part (J) arises by a very strong tendon from the mar- 
gin of the acetabulum. 
The second part (#”) springs from the anterior margin of the 
ilium, in common with the tendon of the internal oblique. 
The third part (F”) takes origin from the posterior margin of the 
ilium, between the origins of the gluteus primus and the ilio-peroneal. 
Passing downward these three parts unite with the deeper exten- 
sor muscles of the thigh. 
Vastus externus (figs. 2& 17, V. #). This muscle arises from 
the lower half of the outer side of the femur. Distally it fuses with 
the other extensors. 
* P.Z.8. 1867, p. 791. t Ibid. 
