OF GALLINACEOUS BIRDS AND TINAMOUS. 177 
To return to the tympanic ossicles of the Hemipodius (Pl. XXXIV. fig. 1, ¢. 1 & t.2). 
They are relatively amongst the largest in the whole class, the bird that comes next them 
being the little Ring-Dotterel (Charadrius hiaticula). In the latter bird the largest bone 
is club-shaped and curved, and although forming not much more than a quadrant, yet 
shows itself to be the unmistakeable homologue of the more than semicircular ‘‘ annulus ”’ 
which is attached to the additional ‘‘ pterapophyses ” of the sphenoid in the Hedgehog’s 
skull. The deficiency of the ornithic bone is, however, supplemented by a small ossicle ® 
which underlies the commencement of the Eustachian tube: the larger bone runs along 
the outer margin of the ‘‘ basitemporal.’’ In Hemipodius ——? the lateral tympanic 
is larger and broader than in the Ring-Dotterel ; the anterior bone is also larger, and is 
distinctly kidney-shaped: this latter piece is not so apparent in the skull of H. varius. 
The remainder of the floor of the large Eustachian tube in Hemipodius is formed by the 
junction of the basitemporal with the basisphenoid, the former element becoming more 
and more distinct from the latter anteriorly. Inthe ‘‘ Galline” proper (Pl. XXXVI. 
fig. 6) the basitemporal region is relatively larger than in any other birds, not excepting 
the ‘‘ Anatine ;” and these two groups agree also in the large, anteriorly placed, and but 
little elevated anterior pterygoid processes of the basisphenoid. A comparison of the 
base of the skull of Hemipodius with that of the Quail shows how far the former bird is 
from being truly ‘‘ Rasorial.” 
It would be well to compare together the structure of the whole range of species in 
this group, if they could be obtained; for, even in the two under notice, there is a 
marked distinction, the smaller kind coming sensibly nearer to the Quail than H. varius. 
This may be well seen in the structure of the basisphenoid ; for in H. varius the anterior 
pterygoid process (Pl. XXXV. fig. 1, 6.s.) is further backwards than in its ally(PIl.XXXIV.), 
being, as in the Pigeon, practically, if not absolutely, opposite the middle of the pterygoid 
bone, the facet of which is a somewhat shorter oval than in the small kind, as well as 
being nearer the os quadratum. This is in the highest degree interesting and instructive ; 
for in Pigeons and Plovers (Pl. XX XVII. figs. 1 & 6, pg.) the pterygoid gives off its short, 
flat-faced peduncle at the middle of its inner side, in both cases having the articular facet 
oval, but, whilst small in the former, it is much smaller in the latter. Then in all true 
Gallinacez, viz. ‘‘ Galline ” proper, ‘‘ Tetraoninz,” ‘‘ Cracide,’’ and ‘‘ Megapodiine,” 
the large, long, slightly elevated facet occupies the inner side of the anterior third of the 
pterygoid, this being joined with a similar forward, long, feebly pronounced anterior 
his work on ‘The Human Hand’ (p. 170), to criticise the views of those who, not finding the chain of little ear- 
bones perfect in birds, “ choose,” as he says, “to say that it is the incus, one of the four bones of the chain, which 
is wanting in the bird: and Where is it tobe found? they ask. Here, in the apparatus of the jaw or mandible, 
in that bone which is called os quadratum.” ‘I believe,” says he, “that the slight and accidental resem- 
blance which this bone in the bird has to the incus in man is the real origin of this fancy.”” But the passage 
is too long to transcribe, and I have no doubt that my readers are well acquainted with it, and with its 
sneering remarks upon the materialistic tendencies of anatomy when studied positively, and without constant 
reference to final causes. 
2 52 
