266 PROFESSOR OWEN ON THE GENUS DINORNIS. 



The length of a corresponding impression of the foot of the Ostrich is eight inches ; 

 the breadth of the posterior part of the impression three inches ; the breadth of the 

 distal end of the tarso-metatarsal bone two inches and a half. According to these pro- 

 portions, the breadth of the distal end of the tarso-metatarsal bone of the tridactyle bird 

 that impressed the Ornithichnites giganteus must have been three inches nine lines ; 

 but the breadth of the distal end of the tarso-metatarsus of the Dinornis giganteus is five 

 inches. According, therefore, to the proportions of the Grnithichnites giganteus, the 

 breadth of the hind part of the foot-print of the Dinornis giganteus must have been six 

 inches, and its length twenty-one inches and a half. 



The genus Dinornis was characterized by a relatively broader foot than the Ostrich, 

 as we know by the tarso-metatarsal bones ; and this bone in the Dinornis struthoides, 

 the third species in point of size, indicates that its bulky body was supported by feet 

 calculated to leave impressions nearly as large as those of the Ornithichnites giganteus. 

 That the toes were as long in proportion to the breadth of the metatarsal bone as in 

 the Ornithichnites, is shown by the two phalanges transmitted by Mr. Williams, the 

 description of which I have reserved for this place. 



The largest of these phalanges is 3^ inches long and \^ inch broad across the proximal 

 joint. This does not present the median vertical ridge which the corresponding groove 

 in the articular surface of the metatarsal indicates the proximal phalanx to possess, and 

 I regard it, therefore, to be a second phalanx, which, as in the middle toe of the Ostrich, 

 would then differ from the first phalanx in the equable concavity of the proximal arti- 

 cular surface. In the second or outer toe of the Ostrich the median eminence is wanting 

 on the proximal end of the first phalanx, but the want of symmetry in that bone shows 

 that it cannot be the analogue of the phalanx of the Dinornis in question, which is 

 almost quite symmetrical. From this character it may be referred to the middle toe : 

 compared with the second phalanx of that toe in a full-grown Ostrich it is relatively 

 longer, less depressed or flattened, the depth of the bone being equal to its breadth ex- 

 cept at the distal articulation, which nevertheless is much less expanded and depressed 

 than in the Ostrich. In this bird the length of the second phalanx of the middle toe 

 is 2^ inches, the breadth of the distal end is l^ inch, and its depth at the middle of 

 the bone 8 lines. In the phalanx of the Dinornis the breadth of the distal end is 1;^ 

 inch, its depth at the middle 10 fines. The size of the phalanx of the Dinornis, re- 

 garded as the second of the middle toe, agrees well with that of the tarso-metatarsal of 

 the Dinornis struthoides. The length of the second phalanx in the Ornithichnites gigan- 

 teus is indicated by the articular eminences in the cast of that impression, and it is a 

 little shorter than the phalanx of the Dinornis above described. 



The smaller of the two phalanges has an unsymmetrical figure, and its proximal arti- 

 cular concavity is continuous with an oblique notch which divides the lower border into 

 two tuberosities. This structure is slightly indicated at the corresponding part of the 

 proximal phalanx of the outer toe in the Ostrich, and in the Bustard is as strongly 



