1883.] ANATOMY OF PH(ENICOPTERUS. 645 



4. The semitendinosus is rather narrow ; it arises from the tip of the 

 postacetabular ridge of the iUum, and from the fascia between this 

 and the pubis. It is inserted (1) into the tendon intersecting its 

 accessorius ; and (2) into a flat tendon which passes round the 

 accessorius to join the tendon of the semimembranosus. 



5. The semimembranosus arises from the hinder end of the 

 ischium, and a small piece of the pubis. Its flat tendon receives, 

 as has already been said, the tendon of the preceding muscle. 



6. The accessory semitendinosus arises from the point of insertion 

 into the femur of the great adductors ; it then goes to the tendon 

 already mentioned, which receives on one side the semitendinosus, 

 on the other its accessorius, and finally goes to join the middle head 

 of the gastrocnemius. 



7. The ambiens is small ; it has the normal relations described by 

 Garrod. 



8. There are three glutei, all of which are large. 



9. The obturator externus arises from the anterior half of the 

 ischium behind the postacetabular foramen. Its origin is fleshy ; 

 its upper surface is tendinous, covered by a thick and strong 

 aponeurosis. 



10. The obturator internus has an oval origin ; round its tendon 

 there is, as usual in birds, a single representative of the gemelli. 



11. The adductor longus is attached to the ischium behind the 

 obturator foramen ; it is inserted into the linea aspera along the 

 distal three fourths of the femur, the ventral face of the inner condyle, 

 the capsular ligament of the knee-joint, and the head of the tibia. 



12. The adductor magnus arises from the external face of the 

 adductor longus ; it is inserted along the outer edge of the middle 

 third of the linea aspera, where it fuses with the accessory semi- 

 tendinosus. 



13. The pectineus arises just internal to the gluteus quartus and 

 is inserted on the inner side of the femur, between the rectus and 

 vastus internus. 



14. The quadriceps femoris is made up of a fused rectus and vastus 

 externus, the vastus internus being distinct. The last-named muscle, 

 as well as joining the common tendon at the patella, has a small 

 separate tendon going to the outer side of the tibial crest. 



15. ^he gastrocnemius B.x'\seshy three heads: — (a) the inner arises 

 from the tendon of the rectus, from the fascia covering the inner 

 surface of the tibialis anticus, and from the cuemial crest of the tibia. 

 It forms a large fleshy belly, which remains distinct from the rest 

 of the muscle till the tendo Achillis. 



(6) The middle head arises by a flat narrow tendon between the 

 condyles of the femur ; it then forms a small belly, joined by the 

 accessory semitendinosus, and then going to the outer head. 



(c) The outer head has a very short thin tendon arising from the 

 outer condyle of the femur, between the biceps sling and the origin 

 of the flexor perforatus et perforans. 



The result of this arrangement is that the muscle has a very curious 

 shape, shown in the accompanying woodcut. 



