MUSCULAR SYSTEM OF AVES. 101 



fibres run nearly parallel with those of the glutcBus minimus^ and 

 terminate in a thin flat tendon^ which similarly bends round the 

 outer part of the femur, to be inserted into the outer and under 

 part of the trochanter immediately below the tendon of the glutcsus 

 medius. This muscle and the preceding portion, or glutcBus mini- 

 mus, are described by Prof. Mayer ^ under the names of c/lutceus 

 quartus and glutcBtis quintus, in the Cassowary ; one of them is 

 absent in most Birds. 



Use. All the preceding muscles combine to draw the femur 

 forward, and to abduct and rotate it inward. 



Iliacus inter nus. This is a somewhat short thick muscle, of a 

 parallelogrammic form, fleshy throughout ; rising from the tube- 

 rosity of the innominatum in front of the acetabulum immediately 

 below the glutcBus minhmis, and inserted at a point corresponding 

 to the inner trochanter, into the inner side of the femur near the 

 head of that bone, which it thus adducts and rotates outwards. 

 This muscle is present both in the Ostrich and Bustard. 



Pyramidalis. The same kind of modification which aflects the 

 iliacus internus, viz. the displacement of its origin from the inner 

 surface of the ilium to a situation nearly external, aflects this 

 muscle. It arises fleshy from the outer surface of the ischium for 

 the extent of an inch, and converges to a broad flat tendon which 

 is inserted into the trochanter femoris opposite, but close to, the 

 tendon of the glutceus minimus, which it opposes, abducting and 

 rotating the femur outwards. 



The adductor hrevis femoris ^ arises from the innominatum im- 

 mediately behind the acetabulum, passes over the back part of 

 the great trochanter, becomes partially tendinous, and is inserted 

 into the back part of the femur in common with the following 

 muscle. 



The adductor longus^ is a long, broad and thin muscle, sepa- 

 rated from the preceding by the ischiadic nerve and artery. The 

 origin of this muscle extends one inch and a quarter from near 

 the upper margin of the innominatum which is behind the aceta- 

 bulum ; it is joined by the preceding strip, and is inserted into 

 the whole of the lower two-thirds of the back part of the femur. 



The adductor magnus^ is a broad and flat muscle, which has 

 an extensive origin (two inches) from the outer edge of the 

 ischium and the obturator fascia ; its fibres slightly diverge as they 

 pass downward to be inserted into the back part of the lower 

 half of the femur, and into the upper and back part of the tibia. 



' XX1X-. p. 12. 2 xr. vol. iii. pi. 32, e. ^ jb.pls, 32, 35, r. 



* lb. pi. 35, G. 



