PROFESSOR OWEN ON THE GENUS DINORNIS. 153 



subcompressed and produced, as if slightly bent, backward. The upper articular sur- 

 face is convex from before backward, almost flat transversely. 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 dimension of this end of the bone is 2 inches 9 lines ; the transverse dia- 

 meter is 1 inch 3 lines. Below 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 insertion 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, r, r', with a median 

 interruption, for the ligamentous attachment of the bone to the fibular ridge of the tibia. 



Metatarsus of Dinornis elephantopus. 



Comparative dimensions of the Metatarse of 



D.gigantens^. D.robustus-. D. elephantopus'. D.crassus. 



in. lines. in. lines. in. lines. in. lines. 



Length 18 6 15 9 9 3 8 8 



Transverse breadth of proximal end 43 46 45 33 



Ditto ditto distal end 5 4 5 3 5 4 3 9 



Least ditto of shaft 2 3 2 2 5 1 9 



Fore-and-aft breadth of proximal end. ... 32 32 210 25 



Circumference of ditto 12 12 9 12 9 3 



Least circumference of shaft 6 3 5 3 6 6 4 6 



Breadth of middle trochlea 110 2 3 2 2 1 8 



Length, following the cun'e 5 9 5 4 5 3 4 



I had, hitherto, regarded the metatarse of Dinornis crassus, described and figured 

 in the ' Zoological Transactions,' vol. iii. pi. 48. figs. 4 & 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 (PI. XLIV. fig. 1), which chiefly 

 on that account 1 have proposed to name elephantopus. Only in the great Maccaws 

 and Penguins do the proportions of the metatarsus resemble those in this most robust- 

 legged of birds ; but the Parrot-tribe present those peculiar modifications of the distal 

 trochleae, with the strong articulation for the back toe, which relate to the Scansorial 

 modifications of the bird's foot ; and the Penguins associate with their broad and short 

 metatarsus a characteristic retention of much of the primitive separation of the three 

 constituent bones. In Dinornis elephantopus these elements have become as com- 

 pletely 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 



' Trans. Zool. Soc. vol. iii. pi. 27. fig. 1. ' lb. vol. iv. pi. 1. ' lb- vol. iv. pi. 46. 



