66 Transactions. — Zoology. 



species was also very powerful. Of the latter the linea aspera is not quite 

 continuous, being repeatedly interrupted at more or less considerable intervals. 

 The form of the proximal orifice is somewhat different from that of II. nioorei, 

 it being more rounded; however, this may be a sexual or even individual 

 peculiarity, and of no specific value. 



Examining the femora of a male and a female Circus, I observe that this 

 proximal orifice in the larger female is also oval, and in the smaller male more 

 rounded ofil 



I have already alluded to the probability that the portions of the two 

 skeletons of extinct birds under consideration might belong to the male and 

 female of the same species, owing to a resemblance in their principal 

 osteological features and to the great disparity of size of many of the I'ecent 

 Diurnal Raptores. 



In order to illustrate this more fully, I would suggest a comparison of the 

 femora of Circus assimilis of both sexes, both belonging to full-grown and 

 mature birds, obtained under similar conditions. 



Certainly, if these two bones had been found in a fossil state, one would 

 not deem it expedient to place them in the same species, owing to their 

 remarkable difierence in size. 



Tibia. 



Harioagornis moorei. PI. VII., Figs. 1 and 2. 



Inches. 

 Total length ... ... ... ... ... 9-52 



Circumference at proximal end ... ... ... 5-48 



Circumference at distal end ... ... ... 4-60 



Circumference of shaft where thinnest ... ... 2-22 



The same pachydermal character, if I may thus express myself, 

 distinguishes also this bone, like all those of the posterior limb of this gigantic 

 species, from any bird of prey known to inhabit New Zealand at present. 



Even in comparing the same with that of Aquila aitdax, of Australia, with 

 which it has otherwise many features in common, this character is well 

 exhibited. 



The form of the surface of the proximal end agrees well in both species, 

 with the exception that the proximal ridge is more rounded off, and the 

 intercondylar tuberosity stands higher in Harpagomis, in which two features 

 the fossil bone agrees more with Circus. 



Two narrow and low intermiiscular ridges are well marked, the first of 

 which begins at the base of the pi-ocnemial process and extends to the inner 

 side of the extensor tendinal canal, above the bony bridge spanning over the 

 precondylar groove ; the other at the termination of the vertical fibular ridge, 

 descending the shaft in a transverse line till it has crossed two-thirds of its 



