BIRDS. 



333 



ar 



s.o 



FIG. 324. Skull of duck, from Wiedersheim. ah, 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; ic, fora- 

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

 process of maxillary; n, nasal; npjc, nasal process of premaxillary ; /, parietal; pg, 

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

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

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



