40 
ON THE CLASSIFICATION OP BIRDS. 
has a little crest just above the nostrils, while in the 
Cyanurus cristatellus {fig. 18.) this form is at its max- 
imum of development. Now, it is quite obvious that 
this is not a crest which admits of beinp; raised and 
depressed at pleasure ; for 
^ I- the feathers are so much 
curled that they could not 
repose flat upon the others, 
as in orilinary crests ; and 
this result w'iU be much 
more apparent on looking 
to the last-named binL 
The next modification is 
when the frontal feathers 
are much longer than those 
on the crown, and form a sharp elevated ridge immedi- 
ately before the eye, without being continued further : 
this, in fact, is but a half crest, and is possessed by very 
few birds, among which Metopin galcata Sw.*, a beau- 
tiful manakin of Brazil, is the most remarkable. Some 
approach is also made to this structure in two other 
splendid little species of the same group — Pipra pareola 
and Pipra caudata 't* ; but their crests are rather rudi- 
mentary. In the third form we see the compressed 
crest in its full development : not only the frontal 
feathers, but the whole of those on the crown are com- 
pressed together so as to be quite compact, and an 
elevated curve overarches the entire head. Those lieau- 
tiful birds, the Rupicola Cagana of South America and 
the Calyptomina viridU of India, afford us striking ex- 
amples of this structure ; where the frontal feathers are 
so long, and so much pointed forward, as to exceed, and 
in part conceal, the bill of the bird. The great crowned 
pigeon of India, gives us likewise a notable and mag- 
nificent illustration of this description of crest, except 
that the pecuhar loose texture of the feathers takes 
from it that compactness, and carinated edge, which are 
so remarkable in the birds just before mentioned. This 
* Brazilian Birds, vol. i. pL SS. 
t Ibid. pi. 45, Vx 
