OF GALLINACEOUS BIRDS AND TINAMOUS. 175 
of its circumference : all the upper portion is formed by the frontal, which is somewhat 
bevelled, especially in H. varius. I am not certain whether there was any portion of 
the nasal gland occupying a superorbital position. The general form of the skull in 
this smaller Hemipodius (H —— 2?) (Pl. XXXIV.) is much more like that of the common 
Quail than that of H. varius (Pl. XXXV.), which is more Pigeon-like and, indeed, has 
its occipital plane much more basal than it is in the small kind. The whole aspect of 
the skull and face of the Hemipodii is, to my eye, very much like that of the nearest 
living relative of the Dodo, viz. Didunculus strigirostris. In both of these Hemipodii 
the parietal region is evenly convex; but whilst in the small kind the parietals and 
frontals pass insensibly into one another in the adult bird, as in the Quail, they retain 
their separate convexities in H. varius (Pl. XXXV. figs. 3 & 4). This condition agrees 
with what is found in the Pigeon, the Lapwing, and the Grouse (Pls. XXXVI. & 
XXXVIL). In H. varius the temporal fossa (PI. XXXV. fig. 4, sq.) is composed of 
three parts, as in the Dodo ; indeed, considering the small size of the bird, these struc- 
tures are singularly like what we see in that large extinct form. These parts are less 
distinct in the small Hemipodius ——?, and are more in the condition of the temporal 
fossa of the Quail. In both kinds the postfrontal process of the alisphenoid and the 
zygomatic process of the squamosal are very rudimentary. In the Quail and its large 
congeners, the ‘‘ Galline ” generally and the ‘‘ Cracidi,” they are long and splintery, 
and in full age become fused together where they meet over the somewhat strong 
temporal muscle. Here again the Hemipodius favours its columbine and pluvialine 
relations (PI. XXXVII. figs. 4 & 9, sq.). The degree in which the lateral and basal 
elements of the occipital sclerotome assist in the formation of the single condyle is very 
different in the various families of birds. In the highest ornithic type, the Crow 
(Corvus), the basioccipital takes the greatest share, the condyle being an evenly convex 
oval, its long diameter lying in the antero-posterior direction. In the ‘‘ Galline ”’ the 
condyle is nearly bifid, being much more indebted to the lateral elements than that of 
the Crow, and having its largest diameter transverse. In the Pigeons (PI. XX XVII. 
fig. 6, o.c.) this takes place in a less degree; whilst in the “ Struthionide”* and in 
Syrrhaptes the condyle is only obscurely dimpled (PI. XXXVI. figs. 1 & 3). ‘The shape 
of the condyle is predetermined in the primordial cartilaginous skull, as may be seen in 
embryo birds before ossification takes place, and whilst the notochord lies in its axis. 
In the Lapwing (Vanellus cristatus) the single occipital condyle (Pl. XX XVII. 
fig.1, 0.c.) is a very neat hemisphere ; whilst in the Hemipodius (Pls. XXXIV. & XXXV.) 
its shape is almost entirely like that of the Crow. Here we are strongly reminded of 
that marvellous little isomorph of the small Gallinacez, the Petroica bicolor (see Osteol. 
Catal. Mus. Coll. Surg. vol. i. p. 299, no. 1584). Certainly this latter bird is the most 
aberrant of the soft-billed songsters ; but whether it can claim any more than a general 
ornithic relationship to the Hemipodius it is impossible to say. We shall see, as we 
proceed, that the vomer of Hemipodius is the exact counterpart of the same bone in the 
VOL. V.—PART III. Qa 
