164 



DR. ST. GEORGE JIIVAET OS' THE 



[Mar. 5, 



extends for a considerable distance forwards and for about half as 

 great a distance backwards, each pair of prolongations slightly 

 diverging as they proceed. The ends of the anterior prolongations 

 are united by cartilage, between which, the isthmus of bone before 

 mentioned, and the two anterior limbs of the entoglossals a vacant 

 space is included which is longer than broad. The dorsal surface 



rig. 1. 



Hyoid of Psittacits erithacus, f . 

 A. Dorsal aspect ; B. Ventral aspect ; C. Lateral aspect. 



Explaiiation of the lettering. 



b, basihyal. 



e, entoglossum. 



c, concavity or cup-like excavation. 

 p, parahyal process (see figs. 1 & 6). 



parahyal arch (see figs. 2, 3, 4, & 5). 



u, urohyal. 

 hh, hypobranchial. 

 cb, ceratobranchial. 



h, symphysis of crura of parahyal arch. 



