GIGANTIC SPECIES OF APTEBYGIAN B1ED. 163 



Beginning with the proximal end of the bone, we find that the intercondyloid tubercle, 

 though relatively higher than in most of the Dinornithidse, does not ascend at such a 

 steep angle from both sides as it does in Apteryx ; moreover, the entocondylar surface, 

 so invariably of an oval shape antero-posteriorly in Dinornis, is more rounded in Megal- 

 apteryx and Apteryx, in both of which the ectocalcaneal process is also broader and 

 more prominent than the entocalcaneal, while the reverse is the case in Dinornis. 

 However, Megalapteryx resembles Dinornis in having the ectocalcaneal process much 

 longer than the entocalcaneal, the former being the shorter in Apteryx. The inner 

 border of the ectocondylar process in Megalapteryx is curved so that its extremity 

 advances somewhat over the flexor tendon, the inner side of the entocondylar not 

 possessing such a curve. The form of the calcaneal groove in Megalapteryx is therefore 

 more irregular and more turned inwards than it is either in Apteryx or in Dinornis, 

 where, however, this feature is slightly indicated. The anterior fossa is much more 

 deeply excavated than in Dinornis, and thus approaches this characteristic feature in 

 Apteryx. The interosseous foramina situated here are separated by a relatively larger 

 space than is found in the Dinornithidse, their entrance being at the same time well 

 defined. The rough surface below the anterior fossa containing that depression down- 

 wards for the attachment of the tibialis anticus tendon is well defined, and resembles 

 in form that of Apteryx. 



As previously stated by Sir Richard Owen \ when pointing out the characteristic 

 features of the tarso-metatarsus of Apteryx : — 



"The meso-metatarse, advancing forwards at its lower half, makes a median pro- 

 minence at that part of the common shaft ; the groove between it and the ectometa- 

 tarse is well marked, and just before its termination it shows a small perforation from 

 before backwards : this is the most distinctive mark between the tarso-metatarse of 

 Apteryx and that of Palapteryx." 



In examining the corresponding bone of Megalapteryx it will be observed that the 

 lower portion of the mesometatarse is also rather prominent, and the groove between 

 it and the ectometatarse better marked than in most of the Dinornithidae ; but 

 what shows more distinctly its close relationship to Apteryx is the occurrence of 

 the same perforation in that groove — thus (if this distinctive characteristic feature 

 holds good, as I have no doubt is the case) at once establishing a marked difference 

 between Dinornis and Megalapteryx. But while in Dinornis and Apteryx both 

 borders of the outer edge of that groove between the condyles are straight, the 

 anterior edge in Megalapteryx advances considerably, and the perforation only passes 

 through that portion of the edge relatively a little more in front when compared with 

 Apteryx. 



The divisional space between the mesometatarse and the entometatarse is also less 



1 ' Memoirs on the Extinct Wingless Birds of New Zealand,' p. 201. 



