18 PTERYLOGRAPHY. 



closely covered the whole body in every part, and did not leave those naked spots, or at least 

 spots destitute of contour-feathers, on which the limbs are more readily moved and in which 

 they fit much better in repose, whilst on the other hand many excessive projections of the body 

 are effaced and concealed by them. There is no question, that every featherless space has 

 some such object, which, however, will be treated of hereafter. For, I believe, that the 

 interrupted feather- clothing must be deduced, as a necessity, from the great size of the contour- 

 feathers ; as, on the one hand, such large structures could not be produced uniformly over the 

 whole surface of the body without a great consumption of organic material and activity, whilst on 

 the other hand, their size must be dependent on the extension and number of the feather-tracts, 

 the latter diminishing in the same proportion as the former are extended and enlarged. 



This view is confirmed by those birds which only possess narrow spaces, as, for example, 

 the Unguirostres, the Steganopodes (Plate X), and the genera JBuceros (Plate VI, figs. 1 and 2) 

 and Coitus (figs. 10 and 11), all which have very numerous, but small contour-feathers on the 

 neck and trunk ; whilst the birds provided with very broad spaces have the contour-feathers in 

 their tracts very large, but few in number. Lastly, those birds which exhibit no spaces, have the 

 wings rudimentary and useless for the purpose of flight, and their feathers are either very small, 

 as in Aptenodytes, LINN., or, if not small, very narrow, as in the Cassowaries. In Palamedea, 

 indeed, a different condition occurs, inasmuch, as the wings are available for flight ; but, 

 on the other hand, the plumage is not truly uninterrupted. (See the Second Part, Fain. 

 Aledorides.) 



CHAPTER III. 

 ON THE METHODS OF INVESTIGATING THE FEATHER-TRACTS AND FEATHERLESS SPACES. 



IN all those birds the young of which are nestlings, and at the same have tolerably naked 

 spaces, the examination of the plumage for the tracts and spaces is very easy, so long as they 

 are in the nest, and the contour-feathers are in course of formation so that they do not cover 

 the spaces ; but even then only in cases where there is no general downy coat. As, however, spaces 

 of this kind do not always occur, and we have not always the opportunity of examining such 

 young birds, some artificial contrivances are necessary to enable us to discover the feather-tracts. 



To effect this three methods are especially applicable : (1), we may carefully pluck the 

 bird, and note the pouches, or pits, in which the contour-feathers were inserted; or (2), we may 

 cut off the contour-feathers at the root, and then wet the body ; or (3), we may strip off' the skin, 

 and after carefully cleaning it, examine it from the inside. In this last method, the contour- 

 feathers reveal themselves at once by the projecting extremities of their tubes. The method to be 

 adopted must depend upon circumstances, but it is always advisable to apply more than one to 

 the same bird, because, according to the individual nature of the bird, sometimes one and some- 

 times another, furnishes the best results. But, after an external examination of the entire 



