254 



GENERAL ORNITHOLOGY 



several special conditions of desmognathism. The parrots are 

 another case ; among other cranial characters of these birds is to be 

 noted the articulation of the palate bones "with the upper beak, like 



that of the zygoma. The multi- 

 farious Picarian birds, or non- 

 passerine Insessores, are desmo- 

 gnathous, excepting the schizo- 

 gnathous trogons (Trogonidce) and 

 the "saurognathous" woodpeckers. 

 Parker has described the follow- 

 ing categories of desmognathism : 

 (a) Perfect direct, the maxillopala- 

 tines uniting below at the mid- 

 line; either with the nasal septum 

 free from such bony bridge, as in 

 a duck; or ankylosed therewith, 

 as in many birds of prey, (b) 

 Perfect indirect, very common, as 

 in eagles, vultures, owls ; maxillo- 

 palatines separated from each 

 other by a chink, but ankylosed 

 with nasal septum, (c) Imper- 

 fectly direct ; maxillopalatines 

 sutured together but not anky- 

 losed. " In young falcons and 

 hawks the palate is at first in- 

 direct, is then imperfectly direct, 

 and at last perfectly direct." (c?) 

 Imperfectly indirect ; maxillopala- 

 tines closely articulated with, and 

 separated by, the "median septo- 

 maxillary " ; but there is no 

 ankylosis, (e) Double : the pala- 

 tines united as well as the maxillo- 

 palatines ; as in the pelican and 



Fio. 70.—^githognathous skull of raven, „n,,vvif...avif ol-mvp notprl in pprtnin 

 Comis corax, nat. size ; from natiu'e by Dr. R. COimOiaUt aOOVe UOteCl, m Certain 



5-r,^!J?,"'''^^'^''',^-^-^-. i^ettei-s as before. Caprimulgine birds, hom-bills, etc. 



N.B. The misplaced reference Ime, V, goes to . -■■ '-' 



the ossifiecl nasal septum borne upon the end (/ ) Compound : when the properly 



of the vomer, which latter bone begins at the -n n ^ ^^ c 



thickest part of the central projection. Mxp a^git/lOguathOUS Skull ot a passer- 



underiies V and overlies Fi, but touches ^^e bird becomes also desmo- 



neither. 



gnathous. 



.SIgithognathism (Gr. alyL9aX6?, aigithalos, some small bird) is 



exhibited almost unexceptionally ]>y the great group of Passerine 



birds ; it is also nearly coincident with Passeres, though a few other 



birds, notably the swifts (Cypselidce), also exhibit it. Huxley's term 



