72 Transactions. — Zoology. 



elegance of form, of which the drawings attached to this memoir will 

 convey an accurate conception better than words can do. 



In the following jiages I shall offer a description of the larger and perfect 

 pelvis, which I assigned to Haoyagornis moorei, whilst the references to that of 

 the smaller H. assimilis will prove the close generic, if not specific, relations of 

 both. 



In comparing the pelvis of H. inoorei with those of Aqidla audax, the 

 wedge-tailed Eagle of Australia, and of Circus assimilis, the Harrier, and 

 Hieracidea novce zealandice, the Sparrow-Hawk of N"ew Zealand, as shown in 

 the following table, the striking difference in size becomes at once manifest. 



Table of Measukements, in Inches. 

 Pelvis of Greatest Lencrth. Greatest Breadth, 



Ilarjjagarnis moorei 

 Aquila audax 

 Circus assimilis 

 Hieracidea novce zealandice 



7-22 .., 3-38 



4-75 ,.. 2-55 



2-75 ... 1-40 



2-00 ... M3 



When examining this table of measurements another peculiar feature of 

 the fossil bone will present itself to our attention, namely, its great length 

 when compared with its breadth ; whilst in the three recent species the double 

 breadth is more than the length, in Harpagornis it is considei'ably less. This 

 peculiarity is produced principally by the greater steepness of the pelvic roof 

 and by the comparatively greater length of the ilio-ischial plates ; moreover, it 

 is also higher in proportion than any of the recent species of Diurnal Raptores 

 with which I could compare it. 



When viewed from below the space formed by the hind part of the 

 neurapophysial crest and the two ilia has an oval shape ; whereas in the 

 three recent species previously alluded to it is shorter, more open, and semi- 

 circular {cb). 



Beginning with the first sacral vertebra, we observe that the articular 

 surface of its centrum is broader in a transverse than in a vertical direction, 

 0-69 inch by 0-58 inch. The neural canal has an oval form, its largest diameter, 

 0'21 inch, being in the vertical line, in this respect resembling Circus; whilst in 

 Aquila, and still more in Hieracidea, the canal approaches the circular form. 



The prezygapophyses {pr) are of middle size and stand forward, their 

 articular surface of a rounded shape, being almost plane. The neural spine is 

 broad and strong at its base, gradually contracting, and forming only near its 

 coalescence a small neurapophysial expansion lying between the iliac plates 

 {n). 



A broad and deep ilio-neural opening is formed on each side of the spinal 

 plate, having a greater vertical than lateral extent, and here again differing 

 from the pelvis of the three recent species previously alluded to, the roof 



