10 



NATURAL HISTORY OF BIRDS. 



The different bones of the head anchylose very early, it being a distinctive char- 

 acter of all living birds to possess a continuous skull-case without sutures; but it must 

 be borne in mind that we know of an extinct group of birds, the Gastornithes, in 



which the sutures were permanent. Notwithstanding a 

 general uniformity in the bird cranium, certain variations 

 of the osteological structure, particularly of the palate 

 and the base of the skull, have of late obtained a great 

 prominence as systematic characters by the investigations 

 of Professor Huxley, and his famous classification of the 

 birds based upon them. Although not prepared to attach 

 so great an importance to these features as has been at- 

 tributed to them by many ornithologists, we will have 

 to pay special attention to them, as in many cases they 

 play a role in the ornithological classification similar to 

 that of the teeth in mammals. 



Professor Huxley distinguished four different types of 

 the palate, which he has called dromceognathous, schizo- 

 ynathous, desmognathous, and tvyithoynatlious, and Pro- 

 fessor Parker has separated a fifth type, which he styles 

 saurognathous. Referring for explanation to the accom- 

 panying cuts, which will give the desired information 

 much easier than the best description, we abstain from 

 any detailed account, only calling attention in a few 

 words to the most salient features. Fig. 2 represents 

 the dromrcognathous structure of the palate, as found 

 in the emu and, with some modifications, in the other 

 ostriches and the tinamous. In 



these, to use Huxley's own words, "the posterior ends of the 

 palatines (pi) and the anterior ends of the pterygoids (pt) are 

 very imperfectly, or not at all, articulated with the basi-sphe- 

 noidal rostrum (-ft), being usually separated from it, and sup- 

 ported, by the broad, cleft, hinder end of the vomer " (vo). The 

 rest of the birds, consequently, have the palatine and pterygoid 

 bones articulating with the sphenoidal rostrum, and not borne 

 up by the posterior ends of the vomer. The arrangement illus- 

 trated by Fig. 3 is the one called desmognathous, since the 

 maxillo-palatines (mxp) are united medially in the palate (des- 

 mos, a bond), the vomer, at the same time being rudimentary, 

 or quite absent, as, for instance, in ducks, flamingos, herons, cor- 

 morants, pelicans, birds of prey, parrots, cuckoos, etc. Fig. 4 

 shows a palate quite different. Here is a cleft between the 

 maxillo-palatines (ma-p), and another between them and tlie 

 vomer (vo), hence the name schizognathous (schizo, I cleave) ; 

 but, in addition to this, the character of the vomer, being 

 pointed in front, is essential, since by this mark the true schi/o- 

 gnathous birds, for instance, the penguins, auks, gulls, snipes, 

 fowls, grouse, pigeons, etc., are separated from another great group of birds, which 

 have the palate " aegithognathous, or sparrow-like, for in these, as exemplified by 



FIG. 2. Under view of the skull of 

 the emu (Dromseognathous); bptp, 

 basipterygoid process of the sphe- 

 noid; mxp, maxillo-palatine; pi, 

 palatine ; pm.r, prsemaxilla ; pt, 

 pterygoid; TO, vomer; It, basisphe- 

 noidal rostrum. 



pmx 



FlG. 3. Under view of the 

 skull of a cormorant (Des- 

 mognathous). The letters 

 as before. 



