IV. 

 The Interlocking of the Barbs of Feathers. 



THE exquisitely beautiful, and remarkably modified epidermal 

 products, which we know as feathers, have probably received 

 more attention than any other form of clothing in the animal 

 kingdom. Science, Commerce, Poetry, Art, and Fashion have each 

 in turn laid them under contribution, a fact which, it will be readily 

 admitted, has been beneficial to all but those most immediately 

 concerned — their possessors, the birds. 



Now we have just implied that feathers are structures with 

 which the world in general is tolerably familiar. To a certain 

 extent this is true ; nevertheless, I have ventured to present the 

 readers of Natural Science with what I hope will prove a concise 

 account of the mechanism, by which the characteristic unity and 

 elasticity of the vane of a typically perfect feather is secured, 

 believing that this will be received not altogether as stale news. I 

 wish it, however, to be distinctly understood that, for the most part, 

 what I have to say will be found little else than a restatement of 

 a tale already told, though in one or two somewhat minute 

 points my claim to originality will, I believe, be allowed to pass 

 unchallenged. 



Before, however, proceeding to the more special subject of this 

 article, it may be well to direct attention briefly to the accompanying 

 diagram of a feather. (Fig. i.) There may be noted (i) the strong 

 pMsint scapHs or stem (Sf.), divided for convenience sake into two parts, (a) 

 a yhachis{Ri) or distal, and(^) a.calamus (c.) — commonly called the quill — 

 or proximal portion, and (2) the rami or barbs (r'), lanceolate processes, 

 seated in two rows, one on either side of the rhachis, and pointing to 

 the tip of the feather. The interstices between the rami, it will be 

 observed, are filled by exceedingly numerous and very small processes, 

 looking to the unaided eye in the natural feather more like bristles, 

 perhaps, than anything else ; these are tlie radii or barbules (r.), and it is 

 mainly with these that we have to deal in explaining the structure of 

 the vexillum (v.) of a feather. The vexillum, it must be remarked, is the 

 compact, well-knit, elastic fringe or web ("beard" as it is called in 

 German), composed of rami and radii interlocked in a manner to be 

 described presently. 



It has just been remarked that the interstices between the rami 



