i8 93 . THE INTERLOCKING OF FEATHERS. 203 



being injured by chafing when in position. The curvature does not 

 seem sufficiently great to account for these notches in the first place, 

 and in the second, seeing that the curve is not delayed till the radius 

 has completed its development, and is then suddenly bent, but that 

 the curvature is synchronous with growth, a far greater inflection 

 could have taken place without any special arrangements, as witness 

 a thousand instances in Nature. Lastly, I would point out that the 

 proximal radii, instead of curving abruptly just at the point where the 

 laminae of the distal radii break up into hooklets, as shown in Wray's 

 figure, are actually not only curved less, but, as already pointed out, 

 extend right across to the next ramus. I have purposely dwelt upon 

 the shortcomings of these figures, because they are rapidly making their 

 appearance into the various text-books. Though this is a fact to be 

 deplored, it may be readily understood. I suppose, nowadays, if one 

 finds himself engaged in bookmaking — of the more honourable kind, 

 I mean — he must add yet more drudgery to his labours, by verifying 

 every statement to its minutest details, when probably, by the time 

 he has finished the last chapter, he will have to begin again and 

 bring his work " up-to-date." 



REFERENCES. 



1. Nitzsch, C. L. — System der Pterylographie. Halle, 1840. English trans- 



lation, Ray Soc., pp. 10, n (1867). 



2. Owen, R. — Anatomy of Vertebrates, vol. ii., pp. 231, 1866. 



3. Huxley, T. H.— The Anatomy of Vertebrated Animals, p. 235 (1871). 



4. Wray, R. S. — On the Structure of the Barbs, Barbules, and Barbicels of a 



typical Penmaceous Feather. Ibis, pp. 420-23, pi. xii. (1887). 



5. Gadow, H. — Bronn's Klassen und Ordnungen des Thier-reichs, iv. Abtheilung. 



Theil i., p. 528 (1886). 



W. P. Pycraft. 



