364 



MR. E. DEGEN ON ECDTSIS. 



observation. This mode of a first acquisition of fii<^ht-feathers equally applies to 

 the rectrices. 



The birds known as Nidifugce, like the Gallhue and most of the game-birds, acquire 

 their flight-feathers shortly after emerging from the egg. The young of the Argus 

 Pheasant is an instance in which flight-feathers make their appearance immediately 

 upon leaving the egg. But we have evidence of much earlier development of flight- 

 feathers than that mentioned above. This is seen in the Wfegapodes (and very probably 

 too amongst the Cracidce), whose young acquire their first set of remiges before ^ they 

 leave the egg. To this character the term of " Ovifugoe " might reasonably be given. 

 Whether or not this first plumo-pennaceous garb be prae- or post-incubate, matters 

 little ; it invariably is heralded in the Dasypcedes by the adventitious plumage referred 

 to above as the truly embryonic one. 



Text-fig. 2. 



Dorsal view of the left-side wing of a young Parrakeet, showing the sessile filamentous plumes 

 of an adventitious plumage (neossoptiles) on the tips of the upper covert-feathers. 



The function of the first set of flight-feathers with their principal coverts in the 

 fledgling being practically the same as that in the more matured individual, structurally 

 it is, nevertheless, inferior and more primitive in texture than that acquired by subse- 

 quent moults. The vanes of the feathers are generally broader, their tips more 

 rounded, the barbs and barbules present a looser union than those which eventually 

 replace them (see remarks made on this point by Brehm (7, 8), also Fatio (19), p. 254). 

 The body-feathers are similarly inferior in substance. Wittmer Stone (44), on pp. 115- 

 117, makes the following statement : — " The remiges and rectrices of the first plumage 

 are usually the same as those of the adult, but the body-feathers, while of the ordinary 

 structure, are much more plwmilaceous ^ than the covering of the adult " — deficient 



' The italics are mine. 



