14 
BEAL'TIFUL BIRDS. 
are chiefly characterised by the enormous size of their 
bill, which gives to their appearance a very singular 
and uncouth character. It is generally as deep at its 
base as the head itself, and of even greater breadth. 
It is uniformly of considerable length, in some species 
equal to that of the whole body, convex and gently 
arched above, and notched along its margin, which is 
extremely thin, by a series of irregular crennlated 
teeth. Although of so large a size it is exceedingly 
light, being composed entirely of thin cellular plates of 
hone, covered on the outside by a horny coating. A 
second equally remarkable peculiarity occurs in the 
structime of the tongue, which is of a firm cartilaginous 
texture, narrow, elongated, and furnished on either 
side with a continued row of fine slender processes 
closely approximated to each other, directed forwards, 
becoming longer towards the tip, and giving to the 
entire organ the appearance of a well -barbed feather. 
In the living birds, the bill is generally beautifidly 
coloured with brilliant prismatic reflections ; but the 
colours fade and the reflections go off entirely after 
