D2, } PTILOSIS OF THE HEAD. 
the occiput more than on the vertex or front, and this gives us the simplest 
and commonest form. Such crests, when more particularly occipital, are usu- 
ally connected with lengthening of nuchal feathers, and are likely to be of a 
thin, pointed shape, as well shown in the kingfisher. Coronal or vertical 
crests proper, are apt to be rather different in coloration than in specially 
marked elongation of the feathers; they are perfectly illustrated in the king- 
bird, and other species of that genus. Frontal crests are the most elegant of 
all; they generally rise as a pyramid from the forehead, as excellently shown 
in the blue jay, cardinal bird, tufted titmouse and others. All the foregoing 
crests are generally single, but sometimes double; as shown in the two lat- 
eral occipital tufts of the “horned” lark, in all the tufted or “horned” 
owls, and in a few cormorants. Lateral crests are, of course, always double, 
one on each side of the head; they are of various shapes, but need not be 
particularized here, especially since they mostly belong to the second class 
of crests —those consisting of texturally modified feathers. It is a general 
—though not exclusive — character of these last, that they are temporary ; 
while the other kind is only changed with the general moult, these are as- 
sumed for a short season only —the breeding season; and furthermore, they 
are often distinctive of sex. Occurring on the top of the head they furnish 
the most remarkable ornaments of birds. I need only instance the elegant 
helmet-like plumes of the partridges of the genus Lophortyx (186); the 
graceful flowing train of the Oreortyx (gen. 185); the somewhat similar 
plumes of the night and other herons. The majority of the cormorants, and 
many of the auks, possess lateral plumes of similar description; these, and 
those of the herons are probably —in most cases certainly — deciduous ; while 
those of the partridges above mentioned last as long as the general plumage. 
These lateral plumes, in many birds, especially among grebes, are associated 
with, and, in fact, coalesce with, the ruffs, which are singular lengthening 
and modifying in different ways of feathers of auriculars, gene and gula; and 
are.almost alwa¥s temporary. Beards, or special lengthening of the mental 
feathers alone, are comparatively rare; we have no good example among 
our birds, but a European vulture, Gypaétos barbatus, is one. The feathers 
sometimes become scaly (squamous) forming, for instance, the exquisite 
gorglets or frontlets of humming-birds. They are often bristly (setaceous) , 
as about the lores of nearly all hawks, the forehead of the dabchick, meadow- 
lark, ete. While usually all the unlengthened head feathers point backward, 
they are sometimes erect, forming a velvety pile, or they may radiate in a cir- 
cle from a given point, as from the eye in most owls, where they form a disk. 
In the foregoing, I only mention a few types, chiefly needed to be known 
in the study of our birds; but should add that there are many others, with 
endless modifications, among exotic birds; to these, however, I cannot even 
allude by name. Peculiarities of nasal feathers, and others around the base 
of the bill, are noticed below. Forms of crests are illustrated in figs. 21, 
22, 23, 24, 32, 56, 95, 96, 107, 109, 114, 117, 125, 127, 135, 136, 152, 
1538, 154, 177, 191, 202. 
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