250 University of California Publications in Zoology fVoL. 13 



ventral lines as here defined. Inner and outer, as applied to vanes, are 

 used to mean respectively the vanes adjacent to and away from the 

 next overlapping feather. Proximal and distal, as applied to entire 

 barbules or vanules, refer respectively to those on the side of the 

 ramus nearer to and away from the base of the feather. In all other 

 cases, proximal and distal are used intrinsically with reference to the 

 structure to which they apply; for example, the proximal part of a 

 barb is the less remote, and the distal part the more remote, from the 

 junction with the shaft. Inner and basal are sometimes used synony- 

 mously with proximal, while outer and terminal are likewise used in 

 place of distal. 



Contour Feathers (fig. A). The feathers which form the contour of a bird's 

 body, growing only in the pterylae, and always with well-developed 

 shafts and calami. Eyelashes, ear-coverts, etc., and the semi-plumes of 

 Nitzsch (1867) are considered as modified contour feathers. German 

 synonym: Konturfedern. 



Plumules. Small, downy feathers, more or less concealed, and with shaft 

 never highly developed. They grow either in the apteria or pterylae, 

 or both, often arranged in a definite manner around the contour feath- 

 ers; absent in some birds (Nitzsch, 1867; Coues, 1884; Evans, 1899, et 

 al.). Synonym: down or down feathers, a term for plumules which is 

 objectionable on account of its loose application not only to plumules, 

 but to any feather or part of feather possessing downy structure. Ger- 

 man synonyms: Dunen (Gadow, 1891); Flaumfedern (Wiedersheim, 

 1909). 



FiLOPLUMES. Degenerate, hairlike feathers growing at the base of contour 

 feathers, composed of a slender quill not differentiated into shaft and 

 calamus, and much reduced vanes, the latter usually consisting of only a 

 few barbs and barbules at the extreme tip. German synonyms: Haar- 

 federn, Fadenfedern. 



Down, or Downy Structure (fig. A). That type of feather structure which 

 is produced by elongated, filamentous barbules, as opposed to a pen- 

 naceous structure (fig. A), which is produced by differentiated distal 

 and proximal barbules or modifications of them, i. e., pennaceous bar- 

 bules, as here used. German synonym: Dunen. 



QuiLL (fig. A). The main stem of a feather, including both shaft and cala- 

 mus (Coues, 1884; Beebe, 1906, et al.) . Synonyms: main stem (Nitzsch, 

 1867), scapus (Nitzsch, 1867; Sundevall, 1886; Pycraft, 1893), primary 

 quill (Mascha, 1905). German synonyms: Kiel (Gadow, 1891), Haupt- 

 kiel (Mascha, 1904). 



Calamus (fig. A). The hollow basal portion of the quill, proximal to the 

 superior umbilicus. Synonym: barrel (Newton, 1899), tube (Nitzsch, 

 1867). German synonym: Spule, of general use. 



Inferior Umbilicus. The proximal end of the calamus, where the papilla 

 finally closes after the maturity of the feather. 



Superior Umbilicus. The pore at the distal end of the calamus, at the junc- 

 tion of shaft and aftershaft, or, in some feathers, where the inner and 

 outer vanes meet. Synonym: umbiliciform pit (Nitzsch, 1867; Newton, 

 1899). German synonym : Nahel (Gadow, 1891). 



