NESTLING FEATHERS OF THE MALLARD. 615' 



and in the following year an important paper by Mr. Pyoraft on 

 the Emperor and Adelie Penguins was published which deals 

 with the composition and sequences as well as with the structure 

 of nestling feathers. 



Dr. Clarke refrained from stating whether the silky-white 

 protoptile coat, or the grey far-like mesoptile coat, of the Ringed 

 Penguin, corresponds to the nestling coat worn by newly-hatched 

 chicks and ducklings. But Mr, Pycraft, in discussing the 

 sequences of nestling-feathers, states that there are good reasons 

 for assuming that in most of our common birds the first or 

 protoptile coat has been lostj and adds that the feathers forming 

 the adult coat of the Emu maght possibly consist of mesoptiles. 



Whether ornithologists have, as a rule, adopted Mr, Pycraft's 

 views it is impossible to say, but it may be mentioned that 

 Mr. Ingram, in tiie ' Ibis ' paper already referred to, points out 

 that a study of the nestling plumage of the Raptores suggests 

 that in some cases, at any rate, it is the second and not the first 

 generation of nestling "down" that has been suppressed (1). 



When, some years ago, I was led to study the feathers of 

 Penguins, I assumed that birds with only one nestling coat had 

 lost the first or protoptile coat ; but the examination of a 

 number of nestlings soon made it evident that when in the Galli 

 and Anseres there is only one generation of nestling feathers,. 

 it is owing, not to the absence of the protoptiles, but to the 

 suppression of the mesoptiles. 



In the account of the nestling feathers of the Emperor 

 Penguin, Pycraft states that the mesoptiles are umbelliform, and 

 that in the Adelie Penguin the mesoptile is in part attached to 

 the main shaft, but mainly to the aftershaft. I have not had an 

 opportunity of studying the nestling feathers of either the 

 Emperor or Adelie Penguins, but from material pkiced at my 

 disposal by Dr. Eagle Clarke I have Avorked out the structure 

 of the mesoptiles of the Ringed Penguin. In this species the 

 mesoptile is extremely complex : it consists (1) of an outer smalt 

 series of barbs, which extends betAveen the protoptile and the tip 

 of the true feather, and hence occupies the position of, and 

 doubtless represents, a shaft ; and (2) of an inner series of barbs 

 (text-fig. 3), arranged to form two or three bundles, which as 

 obviously represent an aftershaft. The chief connections of the 

 mesoptile in the Ringed Penguin are diagrammatically repre- 

 sented in text- fig. 4, which indicates that the mesoptile Consists 

 of a simple shaft extending between the protoptile and the tip of 

 the true feather, and a complex aftershaft connected with the 

 shaft as well as with the aftei'shaft of the true fea,ther. 



In a Mallard duckling at the end of the fifth week the 

 mesoptile looks as if it would develop into a simple umbel not 

 unlike the umbelliform protoptiles of Penguins. But this 

 appearance is due to the fact that nestling feathers, like true 

 feathers, are developed, not out of a scale-like plate, but out of an 

 epidermic tube suiTounding a highly-vascular dermic pulp and 



