360 



very nearly an equal circumference of the middle of the shaft, and a quite 

 equal breadth of the distal end, the antero-posterior diameter of the 

 condyles being also the same in both. If the comparison of these two 

 femora be pursued into further details, it is seen that the anterior margin 

 of the great trochanter is more produced but narrower in No. 1575 than 

 in No. 1578, that the anterior surface of the shaft is more convex, and that 

 the anterior curve of the outer condyle is shorter in the longer femur, No. 

 1575 : the antero-posterior diameter of the great trochanter and of the 

 shaft, especially of that part leading to the outer condyle, is less in the 

 longer femur. With regard to the configuration of the popliteal space, 

 the same differences exist between the femur of the Dinornis dromioides 

 and that of the Din. didiformis, as have been already pointed out between 

 the femur of the Dmornis dromioides and that of the Din. struthoides, 

 viz. a circumscribed tuberosity in place of a continuous ridge in the pre- 

 sent femur, and a deeper and smaller instead of a shallower and larger 

 concavity. 



1579. The half of a longitudinally bisected femur of the Dinornis didiformis. 



A small portion of the parietes at the posterior part of the proximal end 

 of the shaft has been broken away, which exposes a few shallow cancelli 

 but no canal leading to the cavity of the shaft : this is a true medullary 

 cavity, remarkable for the great thickness of its compact parietes. A 

 few oblique laminae break the . continuity of the smooth, imperforate, 

 inner surface of the medullary cavity ; they become more numerous to- 

 wards the two extremities of the bone, which are principally occupied by 

 a coarse cancellous structure. 



1579 1 . The half of a longitudinally bisected femur of a young Emeu of corre- 

 sponding size with the preceding specimen. It shows the air-canal con- 

 tinued from the wide aperture at the back part of the neck of the femur 

 into the cavity of the shaft ; the thin compact walls of that cavity ; the 

 delicate bony lamellae forming the inner wall of the air cavity and reduced 

 in a great part of its extent by the numerous perforations to the state of 

 lace -work. Presented by Professor Owen. 



1580. A transverse section of the half of a longitudinally bisected femur of the 



