94 STRUCTURE AND CLASSIFICATION OF BIRDS 



Semimembranosus, 1 Arises from the iscliium, sometimes 

 trenching a little upon the pubis. It is inserted upon the 

 tibia. The variations which it shows are mainly of size. 

 In Plio&nicopterus it is two-headed, and in certain Falconidee 



i us 



ID 



FIG. 51. LEG MUSCLES OF Palamedea, INNER VIEW (AFTER BEDDARD 

 AND MITCHELL), ILLUSTRATING BICEPS AND ITS SLING. 



completely double. It is often inserted in common with 

 the semitendinosus. 



Adductors.' 1 - -These are, as a rule, two broad, flat, fleshy 

 bands, which arise from the pubis, and from the iscliium, 

 and are inserted upon the inner edge of the femur. The 

 separation between the two parts is less in some birds than 



' Ischio-flexorius ' (GAM>\V). 



'-' ' Pub-ischio-femoralis ' (GADOW). 



