532 



APPENDIX. 



H. The Outer Covering {Indumentum). 



142. Outer covering (Indumentum; Ptilosis). The exterior of the bird in detail. 



143. Feathers (Plumce). Composed of the stem and the webs. 



144. Stem (Scapus). The entire central axis of the feather. 



145. Quill ( Calamus). The hollow horny basal portion of the feather. 



146. Shaft (Rliachis). The solid terminal portion of the stem in which the fibres 



are implanted. 



147. Webs [Pogonia). The series of fibres implanted on each side the shaft, generally 



stiff, and having little 



148. Hooks or barbules along the edges, by which adjacent ones interlock; sometimes 



soft, with the barbules not interlocking, the barbules sometimes wanting. The 



149. Inner web (Pogonium internum) is situated on the inner side of the shaft ; the 



150. Outer (externum), on the outer side. 



15L Vane ( Vexillum). The shaft and webs taken together, or the portion of the feather 



left when the barrel or quill is cut away. 



