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TAIL-COVERTS AND RECTRICES. 37 
eral plumage, and the last one, called coccyx or vomer (L. vomer, a plough- 
share), is large and singularly shaped, and the feathers are stuck around this 
like the blades upon a lady’s fan. The whole bony and muscular apparatus 
is familiar to every one as the “pope’s nose” of the Christmas turkey ; and 
in descriptive ornithology the word “tail” refers solely to the feathers, all of 
which grow upon the pteryla caudalis (§9, b). The tail feathers, like those 
of the wings, are of two sorts; coverts (tectrices) and rectrices (L. rectrix, a 
female ruler or governess; here in the sense of a steerer or rudder, because 
they guide the bird’s flight) ; these correspond precisely to the wing-coverts 
(§ 59) and the remiges (§ 60, a). The 
§ 66. Tait-coverts are the numerous, generally rather small, in compar- 
ison with rectrices, feathers that overlie and underlie the rectrices, defending 
their bases, and contributing to the firmness and symmetry of the tail. An 
obvious division of them is into an wpper (tect. superiores) and under (tect. 
inferiores) set. Neither set is EVER wholly wanting; but sometimes one or 
the other, and particularly the upper, is very short, and not distinguishable 
from the general plumage of noteeum (§ 38), as in the ruddy duck (genus 
270). The upper coverts are the most variable in size, shape and texture. 
While usually shorter than the under, and reaching only from a fourth to a 
half of the length of the rectrices, sometimes they take an extraordinary 
development, project far beyond the rectrices, and form the bird’s chiefest 
ornament. The gorgeous argus-eyed train of the peacock is upper tail 
coverts, not rectrices; the elegant plumes of the paradise trogon (Pharo- 
macrus mocinno), several times longer than the bird itself, are likewise 
coverts. The under tail ccverts are more uniform in development, and 
very rarely, as in some of the storks, become plumes of any considerable 
pretensions. Ordinarily, they are about half as long as the tail, but fre- 
quently reach its whole length, and form a dense tuft, as in the ducks. I do 
not now recall an instance of their projecting noticeably beyond the tail. 
It is to this bundle of under tail-coverts that the word crissum (§ 39) prop- 
erly applies. The 
§ 67. Recrrices or true tail feathers can almost never be confounded 
with the coverts : they are, like the remiges, stiff, well-pronounced feathers, 
pennaceous to the very base of the vexilla, wanting after-shafts (at least 
evident after-shafts, in the great majority of cases), and have one vexillum 
wider than the other, except, sometimes, the central pair. They are always 
in pairs: that is, there is the same number on each side of the middle line of 
the tail, and their number, consequently, is always an even one. The ex- 
ceptions to this rule are so few (and then only among birds with the higher 
numbers of tail feathers) that they are probably to be regarded as simple 
anomalies, from accidental arrest of a feather. They are imbricated over 
each other in this way :—The central pair are highest, and lie with both their 
webs over the next feather on either side (the inner web of either of these 
middle two underlying or overlying the inner web of the other); and they 
all thus successively overlie each other, so that they would form a pyramid 
