152 THE STRUCTURE AND LIFE OF BIRDS cnap. 
horny tube that overlies the papilla. Of this tube one 
side only, as a rule, is much developed, the other, that 
forms the after-shaft, being stunted. The little pit at 
the top of the quill is the remains of the aperture 
through which the pulp once forced its way, extending 
even to the top of the rachis (U2, fig. 38). 
The pulp retires when the feather is complete, 
leaving only a few white flakes in the quill to mark 
its former presence (P). When the feather is to be 
moulted the papilla revives. 
Varieties of Contour Feathers. 
Contour feathers is a general name for the feathers 
which are visible on the surface and which shape the 
bird, to distinguish them from “downs,” “thread- 
feathers,” and “ powder-downs.” 
The name plumes is generally reserved for feathers 
which are merely ornamental or a protection against 
cold. They have not that perfect system of inter- 
locking that makes the wing and tail feathers air- 
proof. To the great wing feathers, the name remiges— 
ze. rowers—is given. Some spring from the hand and 
are called primaries. The Pigeon has eleven such 
feathers, six of them attached to the second meta- 
carpal bone, the rest to the bones of second and third 
digits. If, as often happens (in the Starling, for in- 
stance), the outermost is very short, it is called a bastard 
primary. The “thumb” carries no primary feathers.’ 
The rest of the remiges, called secondaries and inner- 
1 See p. 42 on the question whether this is really the thumb. 
