PROFESSOR OWEN ON THE GENUS DINORNIS. 241 
of breadth to length of the body of the bone are preserved; but the deep anterior 
emargination of the Kivi’s breastbone is not indicated in any species of Moa of which 
the sternum is known; nor have any of them shown the unossified spaces observed in 
the body of the sternum of some individuals of Apteryx, as in that described in the third 
volume of the ‘ Transactions’ of the Zoological Society, and figured in pl. xxxix. fig. 2. 
But, on the whole, the sternum in Dinornis has a closer essential resemblance to 
that in Apteryx than to that of any of the existing Struthious or flightless birds, as 
will be shown in the following comparisons. 
In previous Memoirs “On Dinornis,” descriptions and figures of the sternum have 
been given in the ‘Transactions’ of the Zoological Society. From a mutilated 
specimen, referred to D. giganteus', characters were deduced, especially of the anterior 
and lateral borders, differentiating the bone from that of the Kivi (Apteryx australis, 
ib. fig. 8), and from the sternums of the known existing genera of large wingless birds 
(ib. figs. 4-7). Ina later Memoir? are given a description and figures of a less mutilated 
and smaller sternum, repeating the generic characters of the preceding, but differing in 
the minor breadth as compared with the length; this subject was chiefly valuable as 
verifying the conjectural outline restoring the form of the entire bone in D. giganteus 
in a previous Memoir. I am still unfurnished with grounds for positive determination 
of the species to which the subjects of pl. iv. of the undercited volume can be referred’*. 
In size it accords with that of Dinornis didiformis. The third modification of dinor- 
nithic sternum was shown by an entire specimen of that of D. rheides*; the fourth by 
a somewhat mutilated specimen of the sternum of D. elephantopus’ ; a fifth by an entire 
one of D. robustus, and a sixth by that of D. maximus. 
Of these modifications of the dinornithic type of sternum that (Pl. LV.) of Dinornis 
parvus most resembles the subject referred to in note 2. It is absolutely smaller, and 
is longer in proportion to its breadth, thus making an approach to the form of that of 
D. rheides, in which the character of length is in excess. 
In the breadth and terminal integrity of the mid production of the hind border 
(ib. figs. 1, 2, g), the sternum of Dinornis parvus resembles that of D. elephantopus ; 
in the minor degree of divergence of the side processes (ib. ib. h, h) it resembles that 
of D. rheides. From this it differs in the greater relative breadth and minor length 
of these parts of the hind border of the sternum, in the relative length and breadth 
of which parts D. parvus more resembles D. giganteus. But the indication of the 
terminal notch of the mid process (g) is very feeble in the diminutive species; and 
the foramen above the deeper mid notch of that part in D. rhetdes is wanting in 
D. parvus. With the figures of the breastbone of the present species (Pl. LV.) of 
the natural size, statement of dimensions may be dispensed with. 
? Trans. Zool. Soc. vol. iii. 1846, p. 316, pl. xiii. figs. 1, 2, 3, ? Thid. vol. iv. 1850, p. 17, pl. iv. figs. 1-4. 
* Thid. vol. vii. 1868, p. 116, pls. viii., ix. * Tbid, vol. vii. pl. viii. 
° Memoirs &e., 4to, 1868, p. 118, pl. vii. 
VOL. XI.—PART vill. No. 2.—January, 1883. 2P 
