466 



MANUAL OF ZOOLOGY 



istic parts of the bird's skeleton. It is a broad plate of bone 

 produced ventrally, in the sagittal plane, into a deep keel or 

 carina sterni (car) , formed, in the young bird, from a separate 

 centre of ossification. The posterior border of the sternum 

 presents two pairs of notches, covered, in the recent state, 



;jv; 





s.an an 



;. 279. — Columba livia. Skull of young specimen. A, dorsal; B, ventral; C, 

 left side. al. s, alisphenoid; an, angular; ar, articular; b 0, basi-occipital; 

 d. dentary; e. o, ex-occipital; en, aperture of Eustachian tube; f. m, foramen 

 magnum ;/r, frontal; i. 0. s, inter-orbital septum; ju, jugal; Ic, lachrymal; lb. s, 

 lambdoidal suture; m. etk, mesethmoid; mx, maxilla; nix p, maxillo-palatine 

 process; na, na , na" , nasal; o. c, occipital condyle; or.fr, orbital plate 01 

 frontal; pa, parietal; pa. s, parasphenoid (rostrum); //, palatine; / mx, pre- 

 maxilla; />;■, pterygoid; qu, quadrate; s. an, supra-angular; s 0, supra-occipital- 

 sq, squamosal; ty, tympanic cavity; II— XII, foramina for cerebral nerves. 

 (From Parker's Zootomy.) 



