SKULL OF THE AGITHOGNATHOUS BIRDS, 301 
In my former part (pl. liv. figs. 1-13) I gave two instances (in one family) of a type 
in which we were able to see Aigithognathism begin. It was acknowledged candidly that 
the space between that type (Zurnix) and the lowest of the Passerines was very great ; 
yet these birds, so few steps above the Ratitz, were found to have several most marked 
and unmistakable points of agreement with the Passerines. 
The same friend to whom I owe the adult Hemipod, viz. Osbert Salvin, Esq., F.R.S., 
has kindly supplied me with three entire skeletons of that remarkable Chilian bird, 
Thinocorus rumicivorus. 
As to its skeleton generally, this bird is, broadly speaking, a Plover; but its skull 
forbids it being placed with the true “ Charadriomorphe.” I rather incline to add it 
and some others to the ““Geranomorphe ;” that can be done without calling it a Crane, 
which would be absurd if the term were applied strictly in a zoological sense. 
Example 70. Skull of Thinocorus rumicivorus!. Family Thinocoride. 
Suborder Geranomorphe. 
Habitat. Chili. 
This bird, no larger than a Dottrel Plover, has combined in its face several of the 
characters of other groups, viz. the Dromzognathe, Schizognathe, and Agithognathe ; 
it is therefore not surprising that in seeking for its place in nature some difficulty was 
felt. In its body there is little difficulty: it is a Pluvialine bird, clearly; the whole 
form, texture, and condition of the bones put this into light at once; and, although it 
has only one pair of emarginations on the hinder part of the sternum, it is not alone 
in having that character; for it agrees thus with the Parride and with the common 
Snipe (Scolopax gallinago). 
Professor Huxley’s description of the Dromeognathous palate of the Tinamou is as 
follows. “It has,” says he, “a completely Struthious palate. In fact, the vomer is 
very broad, and in front unites with the broad maxillo-palatine plates, as in Dromeus, 
while behind it receives the posterior extremities of the palatines and the anterior end of 
the pterygoid bones, which are thus prevented, as in the Ratite, from entering into any 
extensive articulation with the basisphenoidal rostrum” (P. Z. S. 1867, pp. 42, 426). 
This matter will be best understood by reference to the morphology of the palate. It 
is characteristic of the Carinate, in which the original parts are metamorphosed to their 
uttermost, that those palatine productions of the mandibular arch, the pterygo-palatine 
bars, should approximate beneath the great trabecular beam. In most cases they meet 
and unite by strong ligaments gliding beneath the fused elements of the trabecule: in 
some, as Storks, Pelicans, &c., they coalesce extensively beneath that beam; and in 
others a key-stone piece or commissural element is formed. This latter condition may 
be due to the fusion of a pair of ossifications (mesopterygoids), as in the Barn Owl; or 
it may be a primarily azygous bone, as in Woodpeckers, or there may be a fore and 
1 See Garrod on Attagis, P. Z. 8. 1877, pp. 413-418. 
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