BIRDS. 



333 



<bt 



\-p* 



oe.c \ f-M 

 6.0 



B 



FIG. 324. Skull of duck, from Wiedersheim. a/s, alisphenoid; ag, angulare; 

 apf, foramen palatinum anterius ; ar, articulare ; bo, basioccipital ; bpg, basipterygoid ; 

 bs, basisphenoid ; bt, basitemporal ; d, dentary ; en, external nares; eth, ethmoid ; eo, 

 exoccipital ; eu, Eustachian opening; fm, foramen magnum; fr, frontal; if, fora- 

 men for internal carotid ; j, jugal ; If, lachrymal ; mx, maxilla ; mxp, palatine 

 process of maxillary; , . nasal; npx, nasal process of premaxillary; /, parietal; pg, 

 pterygoid; //, palatine; pn, posterior nares ; ps, presphenoid ; px, premaxilla; q, 

 quadrate ; qj, quadratojugal ; so, supraoccipital ; sq, squamosal ; ty, tympanic cavity ; 

 v, vomer ; II, V, IX, X, XII, openings for corresponding nerves. 



