Haast.— 0/i the Extinct Genus Harpagovnis. G5 



metatarsus, it will be seen that in Harpagornis the former is longer than the 

 latter limb bone, in this respect resembling Aquila, whereas in Circus the 

 opposite is the case, the metatarsus being longer than the femur. This, to a 

 minor extent, we observe also in Hieracidea. However, when we take the 

 united length of the three principal leg bones into consideration, and compare 

 them with the three principal wing bones, the result is quite different. 



Thus, whilst the wing bones of H. assimilis are only 1-52 inches longer than 

 the leg bones (20-88 inches to 22*40 inches) in Aquila, they are, notwith- 

 standing their smaller dimensions, 5-28 inches longer (16-57 inches to 22.03 

 inches) ; Harjoagornis here again agreeing more with Circus (10-52 inches to 

 11-34 inches). 



According to their different proportions, the wing bones of H. assimilis, when 

 compared with Aquila audax, ought to be 27"53 inches, instead of 22-40 inches 

 their actual size ; and, with Circus, 22-50 inches, a result which closely agrees 

 with the above measurement. Oi. H. moorei we possess only the ulna, the length 

 of which, 10-06 inches, compared with the same bone in the smaller H. assimilis, 

 9-35 inches, would give for the whole wing bones a total length of 24-10 

 inches, instead of 29-62 inches, as calculated according to the measurements of 

 Aquila audax. 



I wish also to point out that in Hieracidea the united length of the wing 

 bones is actually less than that of the leg bones (7-38 inches to 6-61 inches), 

 although this little bird is remarkably strong on the wing. 



Femur. 



Harpagornis moorei. Trans., Yol. IV., PL X., Fig. 1. 

 In my former notes on Harpagornis I offered a short description of the 

 femur (vol. iv., p. 193), comparing it at the same time with the corresponding 

 limb bone in the skeleton of Palioaetes leucogaster, the white-bellied Sea-Eagle 

 of Australia, and of Circus assimilis, the New Zealand Harrier ; but I shall, 

 in the following notes, compare all the principal bones of Aquila audax, the 

 largest Australian species of Diurnal Jia^ytores, with those of the extinct New 

 Zealand bird. 



Har2)agornis assimilis. 



Indies. 

 Total length of femur ... ... ... ... 6-09 



Circumference of proximal extremity ... ... 4-10 



Circumference of distal extremity ... ... ... 4*83 



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



This bone, besides being of smaller dimensions, is somewhat sligliter in its 

 form, otherwise the description as given of that of Harpagornis moorei closely 

 corresponds in all its principal points. There is no doubt, judging froui the 

 insertion marks of the muscles and tlie intermuscular linear ridges, that tins 



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