12 W. P. PYCRAFT. 



here than outline the facts which showed me the need of some such inquiry as that on 

 which we have embarked. 



These three plumages are developed, in anything like completeness, in but a few 

 groups. But they can be followed in the owls for example, with one remarkable 

 exception. In the Tawny, or Eagle Owl, for instance, it will be found that the nestling 

 is at first clothed in long, woolly down ; later, before quitting the nest, this is replaced 

 by feathers, having a superficial resemblance to down, but which, when examined, are 

 found to be intermediate in character between down feathers on the one hand and 

 definitive feathers on the other. Down-like in their softness, they are yet feather-like 

 in their colouration, and in that each feather is made up of a main shaft, rami, and radii, 

 whereas the down feather is umbelliform. But while the head and trunk are thus 

 clothed the quill and tail feathers are those of normal definitive feathers, and functional. 

 This plumage is worn till the autumn, when the trunk feathers at least are replaced by 

 new, and these of the typical adult structure. The exception referred to is found in the 

 nestling barn owls. These birds have the down succeeded immediately by contour 

 feathers, indistinguishable from those of the parent. To this we shall refer again 

 presently. 



This second generation of feathers we may call provisionally " mesoptyles." The 

 penguin must certainly be regarded as having preserved what must be looked upon as 

 a somewhat, perhaps very, ancient succession of plumages, but in these birds the 

 " mesoptyles " have degenerated to mere down feathers. The megapodes, as is already 

 known, shed their down feathers within the egg and emerge feather-clad. But these 

 feathers, as I pointed out some time since (14, 15), differ conspicuously from the 

 feathers which follow the next moult. In the light of my recent discovery the true 

 interpretation of this plumage is clear it is a mesoptyle dress. The differences between 

 the " down " feathers of the Galli and Anseres now become capable of interpretation. 

 They do not, as I imagined, represent a primitive type of down feathers homologous 

 with the woolly, and so presumably degenerate, down of, say, the Alcidse, but answer to 

 " mesoptyles." The protoptyle or first generation of feathers would seem to be 

 wanting in these birds, but I had the good fortune to discover small tufts of down 

 adhering to the tips of the mesoptyles of a young Chlcephaga rubidiceps. Thus, then, we 

 may assume that this first generation, since it has not yet been traced, has been lost in 

 all the Galli, and probably all the Anseres save perhaps this species and one or two 

 allied genera. It is significant that the only species in which it has so far turned up 

 has a striped nestling plumage, which is undoubtedly a primitive sign. 



Among the Galli, it is to be noted, the mesoptyles present varying degrees of 

 perfection, in some, as in Meleagris, for example, a rhachis and aftershaft are fairly well 

 developed, while in Tetrao, for example, the mesoptyles have become umbelliform. 

 Similarly in the case of the Tinami. In Calodromits, for instance, the main axis is 

 large and strong, and the rami set fairly close together, while the radii bear a close 

 resemblance to those of the definitive feather. The after shaft is here also as long as the 



