236 PROFESSOR OWEN ON THE GENUS DINORNIS. 



mediately bounds the medullary cavity of the bone, which is about one inch in diameter 

 at the middle, and slightly expands towards the extremities. There is no bone of similar 

 size which presents a cancellous structure so closely resembling that of the present bone 

 as does the femur of the Ostrich ; but this structure is interrupted in the Ostrich at the 

 middle of the shaft where the parietes of the medullary, or rather air-cavity, are smooth 

 and unbroken. From this difference I conclude the Struthious bird indicated by the 

 present fragment to have been a heavier and more sluggish species than the Ostrich ; its 

 femur, and probably its whole leg, was shorter and thicker. It is only in the Ostrich's 

 femur that I have observed superficial reticulate impressions similar to those on the 

 fragment in question. The Ostrich's femur is subcompressed, while the present frag- 

 ment is cvlindrical, approaching in this respect nearer to the femur of the Emeu ; but 

 its diameter is one-third greater than that of the largest Emeu's femur, with which I 

 have compared it. 



"The bones of the extremities of the great Testudo elephantopus are solid throughout. 

 Those of the Crocodile have no cancellous structure like the present bone. The can- 

 cellous structure of the mammiferous long bones is of a much finer and more fibrous 

 character than in the fossil. 



" Although I speak of the bone under this term, it must be observed that it does not 

 present the characters of a true fossil ; it is by no means mineralized : it has probably 

 been on, or in, the ground for some time, but still retains most of its animal matter. 

 It weighs seven ounces twelve drachms, avoirdupois. 



" The discovery of a relic of a large Struthious bird in New Zealand is one of peculiar 

 interest, on account of the remarkable character of the existing Fauna of that Island, 

 which still includes one of the most extraordinary and anomalous genera of the Stru- 

 thious order, and because of the close analogy which the event indicated by the present 

 relic offers to the extinction of the Dodo of the island of the Mauritius. So far as a 

 judgement can be formed of a single fragment, it seems probable that the extinct bird 

 of New Zealand, if it prove to be extinct, presented proportions more nearly resembhng 

 those of the Dodo than of any of the existing Struthionidm. 



" Any opinion, however, as to its specific form can only be conjectural : the femur of 

 the Stilt-bird {Himantopvs) would never have revealed the anomalous development of 

 the other bones of the leg ; but so far as my skill in interpreting an osseous fragment 

 may be credited, I am willing to risk the reputation for it on the statement that there 

 has existed, if there does not now exist, in New Zealand, a Struthious bird nearly, if 

 not quite, equal in size to the Ostrich'." 



The first letter received by me from New Zealand, confirming this announcement and 

 acquainting me with the existence of the specimens described in the present communica- 

 tion, was written by my friend the Rev. Wm. Cotton, M. A. , and has been already published 

 in the Proceedings of the Society'. I now subjoin, by Dr. Buckland's permission, tlie 



' Proc. Zool. Soc. November 12th, 1839. ' Ibid. January 10th, 1843. 



