SKULL OP THE ^GITHOaNATHOUS BIEDS. 301 



In my former part (pi. liv. figs. 1-13) I gave two instances (in one family) of a type 

 in which we were able to see ^Egithognathism begin. It was acknowledged candidly that 

 the space between that type (Tumix) and the lowest of the Passerines was very great ; 

 yet these birds, so few steps above the Eatitae, 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 Salvia, Esq., F.E.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 " Charadriomorphae." I rather incline to add it 

 and some others to the " Geranomorphae ;" 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 Thinocoridae. 

 Suborder Geranomorphae. 



Habitat. Chili. 



This bird, no larger than a Dottrel Plover, has combined in its face several of the 

 characters of other groups, viz. the Dromaeognathae, Schizognathae, and .Sgithognathae ; 

 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 Parridae and with the common 

 Snipe {Scolopax gallinago). 



Professor Huxley's description of the Dromaeognathous palate of the Tinamou is as 

 foUows. " 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 Dromaeus, 

 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 Ratitae, from entering into any 

 extensive articulation with the basisphenoidal rostrum " (P. Z. S. 1867, pp. 425, 426). 



This matter will be best understood by reference to the morphology of the palate. It 

 is characteristic of the Carinatae, 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 trabeculae : 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 Bam Owl; or 

 it may be a primarily azygous bone, as in Woodpeckers, or there may be a fore and 

 ' See Garrod on Attagis, P. Z. S. 1877, pp. 413-418. 



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