78 
The first cursory comparison of the femora, tibia, &c. sufficed for the recognition of 
common characters, by which, notwithstanding their very different sizes, they appeared 
to be generically related to each other, and were readily distinguishable from their ana- 
logues in the skeletons of the existing Struthious birds. 
A much closer inspection and cautious consideration were obviously required, in order 
to determine satisfactorily whether the different-sized bones belonged to different-aged 
birds of the same species, or to distinct species differing in size, Guided by the seldom- 
failing law, that distinctive characters are most strongly developed in the peripheral 
parts of the body, I first collected together and examined the bones of the foot, and for- 
tunately found for comparison three tarso-metatarsal bones of the same side, the left, 
and of very different sizes. 
Metatarsi. (Plates XX a, XXVII. and XXVIII.) 
I shall first premise the common or generic characters of the tarso-metatarsal bone of 
the Dinornis, and, in detailing the subsequent comparisons of the different-sized bones, 
shall refer to them, as afterwards to the tibia, femora, &c., by the numbers they bear in 
the foregoing list, which will obviate much unnecessary repetition. 
The tarso-metatarsal bone of the Diornis consists of the tarsal and of three primi- 
tively distinct metatarsals blended together, and forming, as usual, a single bone, divided 
at the distal extremity into three trochlear articulations, for the three toes. The prox- 
imal articulation presents two concavities, the inner one the deepest, and the dividing 
ridge is slightly produced upwards at its anterior termination into a conical obtuse 
process. At the middle of the back part of the proximal end there are two short and 
thick longitudinal ridges, divided by a deep round groove for the flexor tendon of the 
toes: the ridges are supported by a thick longitudinal eminence, which is continued 
down the middle of the back-part of the bone to a varying distance in the different bones, 
gradually subsiding as it descends. On each side of the upper part of this median 
longitudinal eminence there is a foramen, as in most other birds, from which a shallow 
and narrow longitudinal canal is continued in the larger metatarsi for some distance 
down the bone: there are no other canals, nor any longitudinal angular ridges at the 
back part of the metatarsus ; nor is there the slightest trace of a surface for the attach- 
ment of a hind-toe. On the anterior part of the bone, near the proximal end, there is 
the usual depression, in which the canals continued from the two posterior foramina 
terminate by a single foramen : below the depression there is a rough surface, for the in- 
sertion of the tendon of the tibialis anticus, from which point a median wide and shallow 
channel extends a certain way down, and divides into two shallower depressions, which 
diverge to the interspaces of the distal articular condyles: the margins of all these de- 
pressions are rounded off, and the general surface of the anterior, as of the posterior part 
of the metatarsus, is smooth and rounded; this, with the great breadth of the bone as 
compared with the metatarsi of other Struthionide and tridactyle Gralle, constitutes the 
