338 OSTEOLOGY OF PARID.E, SITTA, AND CHAMPA LUCAS. 



The narial openings are small, a short ellipse in shape, with the ex- 

 ternal process of the nasal continued but a short distance along the 

 premaxillary. 



The transpalatines are subacuminate and, as well as the postpala- 

 tines, much produced downward and slightly backward. 



The prepalatiiies are moderately stout and seem to increase in width 

 with age. 



The manner in which the palatines join the premaxillaries can be 

 seen only in rather young birds, for, with age, ossification invades the 

 membranous anterior portion of the palatal region, not only conceal 

 ing the terminations of the palatines, but forming a line across them 

 that so strikingly simulates a suture as to have .deceived not only the 

 writer, but so keen an observer as Dr. Parker, who has figured this 

 groove as a suture. 



Fig. 1. — a, palatal region of a ratlier young specimen of T'arus Inidsonicus, showing the anterior enrls 

 of the palatines; b, palatal region of an old specimen of Parns hicolor, with the anterior ends of th^ 

 palatines fused with the premaxillaries. Both figures enlarged. 



The mandible has a large elliptical i)erforation, and there are two 

 mandibular sesamoids, one behind and oue at the outer side of the 

 articulation. 



In Parus hicolor the vertebral arteries enter the cranium a little above 

 the foramen magnum, while in the other members of the genus Parus 

 these arteries pierce the skull right on the edge of the foramen. 



Except in this slight particular, 1 find no difference between P. hicolor 

 and its near relatives. 



In the skull of Auriparus we meet witli a departure from that of 

 Parns in the open orbital septum, this consisting of a very slender bar 

 of bone ; otherwise the skulls of the two genera are very similar in- 

 structure. 



The mandibular perforation of Auriparus is very small. 



In ^JiJgithalus the interorbital septun\ is a slender bar, there is no 

 cranio facial hinge, the maxillary and premaxillary are fused, and the 

 vacuitj" at the exit of the olfactory nerves is large. 



The general aspect of the cranium, however, is Parine in spite of the 

 peculiar curve of the beak ; the narial opening are small ellipses ; the ex- 

 ternal process of the nasal is continued but a short distance along the 

 premaxillary. and the prepalatine bars are broad, although they join 

 the ])remaxillaries in a slightly different manner than in Parus. 



