ANATOMY OF THE LEMUROIDEA. 65 
In Lemur xanthomystax it was observed by us to cover the whole of the obturator 
membrane. 
Represented in Galago crassicaudatus (Pl. V. fig. 21, Ob. e). 
The OBTURATOR INTERNUS, which has much tendinous fibre on its surface, arises from 
the whole internal circumference of the obturator foramen, except, perhaps, on its 
upper posterior side. It is inserted immediately above the insertion of the obturator 
externus. 
We consider the tendon very strong in Galago allenii. The muscle in G. erassicau- 
datus is shown in PI. V. fig. 19, and the tendon of insertion PI. VI. fig. 25, O0. 7. 
QUADRATUS FEMORIS.—This is a very voluminous muscle. It arises from the tuberosity 
of the ischium immediately in front of the origins of the biceps and semimembranosus 
(i. e. these origins are superficial to it), but extending slightly further inwards towards 
the middle line of the body and still further outwards. It is inserted into the back of 
the femur for the whole interspace between the insertion of the gluteus maximus and 
that of the adductor magnus. It lies in the same plane as the last mentioned muscle, 
and is intimately connected, on its inner side, with the adductor brevis. 
In L. varius it is shown by Cuvier, ‘ Myologie,’ pl. 70. fig. 2, d. 
Displayed in the dissections of Galago crassicaudatus (Pl. V. fig. 21, and Pl. VI. 
fig. 25, Q. f). 
In Nycticebus it is not large, but is the reverse in Loris gracilis. 
This muscle is not mentioned by Van Campen in Perodicticus; but perhaps he has 
taken the adductor magnus for it. 
In Zarsius it appears to be as in L. catta from the description; but only a small 
portion is represented in Burmeister’s plate 70. figs. 4, 6, no. 12. 
In1acus.—In Lemur catta' it arises from the internal surface of the ilium external 
to the ilio-pectineal line, and is inserted by a tendon common to it and the psoas 
magnus into the peroneal trochanter. 
In the genus Lemur it can hardly be said to be double; but in Galago (i. €. in G. gar- 
nettii and G. allenii) the disposition is not perfectly the same in each animal, although 
it may be considered as arising in two portions. In G. garnettii the portion from the 
ilium is small, and only arises from the anterior superior spinous process of Man. The 
second portion, coming from the body of the last lumbar vertebra, joins the above- 
mentioned; and they have undoubtedly a single insertion, namely, by a strong, flat 
tendon into the border of the tibial trochanter, being very slightly connected with the 
insertion of the psoas magnus, which is fleshy. G. crassicaudatus with this, Pl. V. 
figs. 19 & 20, JI. 
In G. allenii the first or innermost portion arises from the whole anterior border of 
the ilium, excepting as much as is occupied by the second slip. It is inserted into the 
tibial trochanter by muscular fibres. The obturator nerve passes between the upper 
1 Cuvier has only shown a small portion of this muscle in Z. catta, pl. 70. figs. 2 & 3,7, 
VOL. VII.— PART I. K 
