I^E&tLInQ i*EATH6tlS of TSE MALLArD. 633 



III. Origin and History of Feathers. 



It seems to be generally assumed by iiatvu-alists and others 

 interested in birds that feathers are modified scales, and were 

 originally acquired to enable birds to fly- When evidence of the 

 scale origin of feathers is asked for, the reply usually is, " If 

 you accept the view that birds were evolved from Reptile-like 

 ancestors you may safely also accept the view that feathers are 

 specialized scales." Having adopted the view that feathers are 

 modified scales, investigators interested in the coat of birds 

 proceeded to inquire if each feather corresponds to an entire 

 scale or to part of a scale. Wiedersheim favoured the view that 

 each feather represents a complete scale, but Bornstein (13) and 

 others came to the conclusion that a feather papilla only repre- 

 sents a fragment of a scale. 



How scales were transformed into feathers has been indicated 

 by various writers. Baron Frances Nopcsa, in a paper " On the 

 Origin of Flight," states that we may quite well suppose " birds 

 originated from bipedal long-tailed cursorial reptiles Avhich 

 during running oared along in the air by flapping their free 

 anterior extremities," and added that the double running and 

 flapping action would subsequentlj'- easily lead to an enlaxgement 

 of the posterior marginal scales of the antebrachium, and even- 

 tually to their development into actual feathers (10). Lull, 

 another believer in the transmission of acquired somatic charac- 

 ters, points out that the anterior extremities of birds when in the 

 making would be more eflTective if their breadth was increased, 

 and that an increase of the size of the scales along the arm margin 

 would be a ready means to this end. Lull then proceeds to say 

 the "scales would extend, lighten, and ultimately evolve into 

 feathers which would not only subserve the function of flight, 

 but acting as clothing retain and aid in the increase of tempera- 

 ture" (11). (Similar views are held by W. K. Gregory, who tells 

 us the Pro-Aves jumped lightly from branch to branch and 

 finally from tree to tree partly sustained by the long scale-like 

 feathers of the pectoral and pelvic wings. 



The view that feathers are modified scales has long been held 

 by Pycraft. In a work published in 1910 Pycraft points out 

 tliat, to start with, the body clothing of birds probably consisted 

 of relatively large scales, " those covering the hinder border of 

 the incipient wing growing longer would still retain their original 

 overlapping ai-rangement and along its hinder border would in 

 their arrangement, appearance, and function simulate the quills 

 of modern birds; as their length increased they became also 

 fimbriated and more and more efficient in the work of carrying 

 the body through space." 



It is now evident that the wing-quills of birds are preceded by 

 nestling feathers, and may be regarded as modified protoptiles : 

 hence the question at issue is, Are the protoptiles modified scales? 



