ANATOMY OF THE ANTHEOPOID APES. 191 



anterior border between the anterior spine and the glenoid cavity, but also — though to 

 a very slight extent — from the fascia lata and from the septum between itself and the 

 glutceus medius. Its insertion behind that of gluoceus minimus has been already 

 mentioned. The muscle begins to be tendinous on the upper surface rather more than 

 an inch away from the actual insertion, at a less distance on the ventral surface ; the 

 actual tendon of insertion measures about half an inch in length. 



(5) Piriformis runs in close proximity to the glutceus medius ; it ends in a somewhat 

 rounded tendon, which is attached to the femur, on to the great trochanter, between 

 the insertions of the glutcei medius and minimus. 



(6) Obturator interims, together with the gemelli (of which the external is the 

 larger), is inserted into the upper part of the fossa behind the great trochanter. 



(7) Obturator externus has an entirely fleshy insertion just behind the lesser 

 trochanter. 



(8) Quaclratus femoris is fleshy throughout. 



(9) Biceps femoris. — This muscle has two heads; the ischial head arises from the 

 tuber ischii in common with the semimembranosus and semitendinosus ; it forms a 

 round fleshy belly, which is tendinous on the lower surface near its origin, and becomes 

 tendinous on the outer surface about halfway along ; it ends in a flat tendon, which 

 widens out, becoming continuous with the fascia covering this part of the leg, and is 

 also inserted on to the fibula ; this upper part inserted on to the fibula remains thicker 

 than tke rest. The femoral head arises from the femur and from the septum between 

 itself and the vastus externus along a line measuring two inches and three quarters ; 

 its fibres are partly inserted on to the tendon of the long head, and partly become 

 continuous with the fascia covering the thigh. 



(10) Semimembranosus. — This leaves the head of origin common to itself, the biceps, 

 and the semitendinosus as a flat tendon one inch and three quarters in length, and one 

 quarter of an inch in breadth ; it forms a fleshy belly, slightly tendinous on the inner 

 surface at both ends ; it is inserted by a short strong tendon on to the inner side of the 

 tibia below the ligament uniting the tibia and the femur. 



(11) Semitendinosus. — This muscle is rather larger than the last ; it leaves the 

 common muscular origin, which it shares with the last two muscles, almost simul- 

 taneously with them, «'.e., the common head becomes trifurcate. Its tendon of insertion 

 measures rather over an inch and a half in length ; it becomes wider at the actual 

 insertion, which is close to and below that of the gracilis. 



(12) Iliaco-j)soas. — The two separate muscles are inserted by a common tendon on 

 to the lesser trochanter. 



(13) Sartorius. — This muscle is roundish at its origin, but becomes flat and strap- 

 shaped before the middle of the thigh; it is more slender than the gracilis. Its 

 diameter some way in front of the insertion is three fifths of an inch. At its insertion 

 it becomes much wider. The insertion is half tendinous and half muscular, the 



