116 



GEXESAL ORNITHOLOGY. 



have received particular names. A rectrix broad to the very tip, and there cut squarely off. is 

 said to be truncate ; uue sucli cut obliquely off' is incised, especially wlieu, as ofteu happeus, the 

 outline of the cut-off' is concave. A linear reetrix is very uarrou-, with parallel sides: a lanceo- 

 late one is broader at the base, thence tapering regularly aud gradually ti.> the tip. A notably 

 pioiuted reetrix is said to be acute : wheu the piointiug is produced by abrupt centraetion near the 

 tip, as in most woodpeckers, the feather is acuminate. A very loug aud sleuder, more or less 

 linear feather is called Jilainentous. as the lateral pair of a barn swallow or most sea swallows. 

 I'he vanes sometimes enlarge abruptly at the end, forming a spoon-shaped or spatulate feather: 



or such a spoou may 

 result fi'oui narrowing 

 of the vanes near the 

 end, or their entire ab- 

 sence, as in the "■rack- 

 t ■ of a saw-biQ (Mo- 

 nu)tus). The vaues are 

 s uietiuies wa\-y as if 

 limped: our Plotu.s is 

 hue example of this. 

 ■^ metiiues the vaues 

 \u entirely loosened, 

 the barbs being remote 

 ti m each other, as iu 

 tl e exotic genus Stipi- 

 f ■»,<, and some parts 

 t tlie wondei-ful caudal 

 \j peudage of the mah' 

 hie-bird {Menura nu- 

 2)erba). ^Yheu the rha- 

 his projects beyond the 

 \ iiies, the feather is 

 J inij!ie. or better, inu- 

 natc (Lat. mucro, a 

 jucker). as excellently 

 li iwu ill the chimney- 

 ^«ift. Cluetura (tig. 

 'IT). A pair of feathers 

 abruptly extending far 

 beyond the others are 



called lon(]-e,e^erted, after the analogous use of the term in botany. Tail-feathers also differ 

 much in their consistency, from the softest aud weakest, not well distinguished from coverts, 

 to such stiff and rugged props as the woodpeckei'S possess. They are dowuy and very rudi- 

 mentary in a few birds, notably all the grebes, Podicipcdidir. which are commonly said to 

 have no tail. The tiuauious of South America (Dronucognafluc) are also very closely 

 docked. The 



Flo. o2. — The l.yre-binl of .\uslralia. Muiiira sujxiOn. to show the tuiique 

 li/rate shape of the tail. (From Anier. Xat.) 



Typical Number of Keetrices is twelve. This liolds iu the great maioritv of birds. It 

 is so luiiform tlironghcnit the great group Osciues, that the rare exceptions seem perfectly 

 anomalous. In the other group of Pnxseres (Claniatores) it is usually twelve, sometimes ten. 

 Ten is the rule among Picariie. tliough many have twelve, a very few only eight, as in the 

 genus Crotophdija. The whole of the woodpeckers (Pu-id(e) have apparently ten ; but really 



