EXTERNAL ANATOMY. CRESTS. 
41 
deviation, however, leads us to another, of which at 
present we know but of one example, the Cephalopterus 
ornatus of (JeoflProy St. Ilillaire. The crest of this 
extraordinary bird is immensely large, advancing so 
far in front as to 
touch the end of 
the hill, and it is 
compressed in the 
same manner as 
that of Rupicola; 
hut the ends of 
die feathers, in- 
stead of meeting 
so as to form a 
sharp ridge, suddenly recede from each other, curve out- 
wards, and fonn a most elegant drooping line of plumes, 
hanging over on the sides, so as to shade the face like an 
umbrella. The figures that have hitherto been given 
of this rare bird are all taken from the specimen in the 
Paris Museum, and which has been saiUy distorted in 
the setting up ; a minute examination of this specimen 
has convinced us that the frontal feathers, instead of 
being raised over the hill, as Temminck represents 
them, partly repose and overshadow it, at least as much 
as do those of Cahiptomina and llnpieola. Having 
now reached the highest development of this form. 
Nature evinces her usual propensity to return to the 
more simple form of crest, and she therefore unites the 
fixed with the mobile structure. The crests of the or- 
dinary species of Corythaix is precisely of this de- 
scription : that part which occupies the front of the 
head advances forward, and this being the natural 
position of the feathers, gives us the character of a fixed 
crest ; but the hinder part, which is the longest, is not 
altogether compressed, although it cannot be said to lie 
flat on the crown, like those of ordinary birds. 4Te 
have recently had the opportunity of seeing some living 
examples of this genus in which the crest appears to he 
always carried erect; although, judging even from the 
