GIGANTIC SPECIES OF APTEEYGIAN BIED. 167 



Femur. (Plate XXX. figs. 5, 6.) 



Measurements. 



inches. 



Total length 7-80 



Circumference of shaft 2*80 



Breadth of proximal end 2 -05 



Breadth of distal end 2*15 



Diameter of shaft in middle 0"85 



Sir Richard Owen, in his ' Memoirs on the Wingless Birds of New Zealand,' on 

 p. 201, when speaking of the remains of Apteryx found associated with bones of 

 Dinomis in the North Island, in giving some of the principal osteological features, 

 points out that : — 



" The shaft of its femur is characterized by the convexity of the fore part in the 

 direction of its axis, which is due not only to a slight bending of the whole shaft 

 forward, but to an enlargement in that direction of the middle of the fore part of 

 the shaft." 



As in describing the shaft of Megalapteryx I should have to use the same expres- 

 sions, I wish the reader only to refer to the figures attached to this communication, 

 where both bones are given of the natural size, and where this characteristic well- 

 pronounced convexity is well seen, a feature by which both genera are so distinctly 

 separated from the Dinomithidae. 



The femur of Apteryx australis is shown for comparison (Plate XXX. figs. 10 & 11). 



The femur of Megalapteryx has, like the same bone in Apteryx, a well-defined neck, 

 the constriction following round the entire circumference. The articular surface 

 between the head and the trochanter is, however, more deeply excavated in Megalapteryx 

 than in Apteryx, in the latter of which the trochanter has a very slight upward slope, 

 rising scarcely above the head, whilst Megalapteryx in these two features has more 

 resemblance to Dinomis. 



On the post-trochanterian surface the two rough depressions, the upper one for the 

 insertion of the abductor femoris and the lower one standing in advance of the former 

 for the quadratus femoris, are well shown ; but, in comparison with the size of the 

 bones, they are not so deeply excavated as they are in Apteryx. Moreover, there is a 

 marked difference between the form of these depressions in Megalapteryx and Apteryx 

 when compared with the Binornithidee. 



From below the quadratus-femoris depression an intermuscular ridge runs obliquely 

 across to the middle back part of the shaft, where another meets it, which starts from 

 below the head of the bone; below their junction the orifice of the medullary artery 

 is situated. Similar intermuscular ridges run along the shaft of the femur of Apteryx, 



vol. xn. — part v. No. 4. — December, 1886. 2 c 



