188 
ligamentous attachment ofthe rudimental metatarsal of the back-toe (hallux), and also 
by that characteristic bone of the genus Palapteryx (fig. 1, 1). 
The general differences in the proportions of thickness to length will be appreciated 
by comparing the metatarse of Palapteryr robustus, fig. 1, in Pl. XLIX., with the meta- 
tarse of Dinornis giganteus, Pl. XXVII. fig. 1. 
The subject of Pl. XLIX., which was obtained, like most of the bones transmitted by 
Col, Wakefield, from the recent vegetable deposits at the mouth of the Waikawaite, is 
in a much better state of preservation than the bones obtained from the more ancient 
beds of the actual rivers in the North Island, described by the Very Rev. Archdeacon 
Williams, in the letter quoted at p. 75. The relative age of the present North and 
Middle Islands of New Zealand, the question of their original union and of the period 
of their separation—in short, all the geological and geographical deductions from the 
evidence of their organized fossils—depend for their true solution upon a rigorous 
comparison and exact determination of those fossils. 
The principal dimensions and general form of the tarso-metatarsal bone of the Pal- 
apteryx robustus are given in Pl, XLIX. fig. 1, where the anterior surface is represented 
of the natural size ; other dimensions are recorded in the text. The compound nature 
of this bone in birds generally is described at p. 78, and I may here premise that I have 
applied to the principal elements the names of ‘ entometatarse’ (11), ‘ mesometatarse ’ 
(111), and ‘ ectometatarse’ (rv) respectively, for the convenience of description. 
The shaft in Palapteryx robustus is subtriedral in its upper two-thirds, subcompressed 
from before backwards in its lower third, of equal breadth in its middle fourth, and 
thence expands to both extremities, but more to the inner than the outer side, and in 
a greater degree at the lower end; so that the inner margin is more concave than the 
outer one. This difference is not so great in the Dinornis giganteus, in which, also, 
the shaft continues gradually to diminish in breadth towards its lower third. 
The proximal articular surface of the metatarse of the Palapteryx robustus is divided, 
as usual, into two concavities, that for the inner condyle of the tibia being the largest 
and deepest: it is of a triangular form bounded internally by a well-defined edge which 
extends in a nearly straight line from the anterior internal angle to the posterior angle 
of the concavity: the anterior external angle is formed by the prominent fore part of 
the intercondyloid protuberance. The more shallow concavity for the outer condyle is 
subcircular, its outer boundary being convex and most raised at its middle part ; pos- 
teriorly the border subsides and the concavity passes into a convexity at that part. The 
non-articular surface of the proximal end is chiefly behind the concavities and extends 
upon the upper part of the calcaneal processes: these are, as usual, three in number, 
the internal and middle ones being most prominent : they are obtusely rounded, and 
separated by the deep and wide groove for the flexor tendons of the toes: the lon- 
gitudinal extent of the inner process (the entocalcaneal one, fig. 2, ce) measures one 

