BY T. THOMSON PLYNlSf, B.Sc. 



PART II.— MYOLOGY OF THE HIND LIMB. 



Myologicall}^, I have as yet examined only two 

 genera of the Megapodidae — " Catheturus " and 

 " Lipoa." These two genera agree almost exactly in 

 the arrangeme.nt and distribution of the muscles, such 

 differences as are noticeable being in the main due ta 

 the disparity in the length of the hind limb. That ot 

 the Mallee Hen is much shorter than the Brush Turkey, 

 being only three-quarters the length. In both cases the 

 enormous strength of the leg muscles is very noticeable, 

 particularly as regards the muscles of the thigh. The 

 size of these muscles is much greater than in Gallus. 

 The great size of the posterior thigh muscles in these 

 birds results in the drawing out of the post-acetabular 

 portion of the sacral region. The acetabulum, therefore, 

 which lies about half-way between the two ends of the 

 pelvis in Gallus, comes to about one-third of the distance 

 from the anterior end. The enormous thickness of the 

 thigh muscles, anterior as well as posterior, results in 

 the deep hollowing out of the sides of the pelvis ex- 

 ternal to the ilio-ischiatic crest. 



The thigh contains the usual muscles of the Galli- 

 naceous birds, the tensor fasciae, the semitendinosus 

 and accessory semitendinosus, the femoro-caudal and 

 its accessory, and the ambiens. Certain points, some 

 of which may be characteristic, are worthy of note in 

 connection with these muscles. The gluteal muscles 

 are well developed, and are four in number — primus 

 (tensor fasciae), medius, minimus, and quartus — the 

 latter being a short, chunky little muscle having its 

 origin at the posterior outer margin of the ilium for a 

 short distance, and passing backwards, slightly down- 

 wards and outwards, to be inserted into the outer side 

 of femur just below the trochanter and slightly below 

 and anterior to the insertion of the gluteus medius. 



The semitendinosus and its accessory are surpris- 

 ingly well developed, the latter being nearly as long as 

 broad (one and a half by one and a quarter inches). The 

 arrangement of the femoro-caudal muscle is interesting 

 in these genera. According to Garrod (P.Z.S., 1873, pp. 

 626-644) in most birds " it . arises from the (anterior) 



