TAIL-COVERTS AND RECTRICES. 37 



eral pliimnge, and the Inst 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 hony and muscular apparatus 

 is familiar to a^Kiry 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 (k-clrices) and rectrices (L. rectrix, a 

 female ruler or governess ; hero in the sense of a steerer or rudder, because 

 they guide the bird's flight) ; these correspond precisely to tlie wing-coverts 

 (§ 59) and the remiges (§ 60, a). The 



§ 66. Tail-covkkts are the numerous, generally rather small, in compar- 

 ison with rectrices, feathers that overlie and underlie the rectrices, defending 

 their bases, and contriljuting to the firmness and symmetry of the tail. An 

 obvious division of them is into an tijijier (tect. xvperiores') and under (JecL. 

 wferiores) set. Neither set is ever wholly wanting ; but sometimes one ov 

 the other, and particularly the iipper, is very short, and not distinguishable 

 from the general plumage of notteura (§ 38), as in the ruddy duck (genus 

 270). The upper coverts are the most varialjle in size, shape and texture. 

 While usuall}' 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 {PJiaro- 

 macvus mocinno), several times longer than tin; bird itself, are ]ike\vise 

 coverts. The under tail coverts are nicu'e uniform in development, and 

 very rarel}', as in some of the storks, l)ecorae plumes of an}' considerable 

 pretensions. Ordinarily, they are about half as long as the tail, but fre- 

 quently reach its Avhole length, and form a dense tuft, as in the ducks. I do 

 not now recall an instance of their projecting noticeably be^'ond the tail. 

 It is to this bundle of under tail-coverts that the word crissum (§ 39) prop- 

 erly applies. The 



§ 67. Rectrices or true tail feathers can almost never be confounded 

 with the coverts : they are, like the remiges, stilf, well-pronounced feathers, 

 pennaceous to the very Ijase of the vexilla, wanting after-shafts (at least 

 evident after-shafts, in the great majority of cases), and have one vexillura 

 wider than the other, except, sometimes, the central pair. The}' are always 

 in xictirs : that is, there is the same numl)er on each side of the middle line of 

 the tail, and their niunber, consequently, is alwa}s 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 proljably 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 l)oth their 

 webs over the next feather on either side (the iinier web of either of these 

 middle two underlying or overlying the inner web of the f)tlier) ; and they 

 all thus successively overlie each cjther, so that they would form a pyramid 



