Prof. Owen on the Dinornis elephantopus. 173 



styliform bone, 14 inches G lines in length. The head is subcom- 

 pressed and produced, as if slightly bent backwards ; the upper arti- 

 cular surface is convex from before backwards, almost flat trans- 

 versely. The head of the bone is flattened on the inner side, almost 

 flat, but a little convex on the outer side. The fore-and-aft dimen- 

 sion is 2 inches 9 lines, the transverse diameter 1 inch 3 lines. Be- 

 low the head the bone assumes a trihedral form, with the sides 

 convex, gradually tapering, and blending into a shape elliptic in 

 transverse section, and ending in a point about 9 inches above the 

 ankle-joint. The outer surface of the shaft of the fibula is impressed 

 by two oblong rough surfaces for the iasertion of muscles, the upper 

 one 2 inches 9 lines in length ; the inner part, which is ridge-like, 

 dividing the fore from the back surface of the bone, presents a rough 

 surface with a median interruption, for the ligamentous attachment 

 to the fibular ridge of the tibia. 



Dimensions of the Metatarse of D.gigan- D.robustus. D.elephan- 



teus, topus. 



In. Lines. 



Length 18 6 



Transverse breadth of proximal end ... 4 3 



Transverse breadth of distal end 5 4 



Least breadth of shaft 2 3 



Fore-and-aft breadth of proximal end... 3 2 



Circumference of ditto 12 



Least circumference of shaft 6 3 



Breadth of middle trochlea 1 10 



Length of do. following the curve 5 9 



I had hitherto regarded the metatarse of the Dinornis crassus 

 (Zoological Transactions, vol. iii. pi. 48, figs. 4 and 5) as presenting 

 the most extraordinary form and proportions of all the restored 

 species of huge wingless birds of New Zealand ; but it is strikingly 

 surpassed in robustness and in great relative breadth and thickness 

 by the same bone of the present species, which chiefly on that 

 account I have proposed to name elephantopus. Only in the great 

 Maccaws and Penguins do I know of a metatarse with similar pro- 

 portions to that of this most robust-legged of birds. But the Parrot 

 tribe present those peculiar modifications of the distal trochlese, with 

 the strong articulation for the back toe, which relate to the scan- 

 sorial modifications of the bird's foot ; and the Penguins associate 

 with their broad and short metatarse a characteristic retention of 

 much of the primitive separation of the three constituent bones. In 

 the Dinornis elejjhcmtojms these elements have become as completely 

 coalesced as in any other species, and the general characters of both 

 proximal and distal ends accord with those in previously described 

 species. On a more special comparison of the metatarse of the 

 Dinornis elephantopus with that of its nearest congener, the Dinornis 

 crassus, the following diff^erences present themselves : — The cndo- 

 condyloid depression is deeper, its fore-and-aft diameter is greater, 

 and its transverse diameter less, than in the ectocondyloid one ; but 

 the breadth of the endocondyloid depression is relatively greater, and 

 its depth somewhat less in the Dinor7iis elephantopus than in the 



