756 Letters, ExlractSj and N^otes. [Ibis, 



Adult birds are clothed with down and feathers, the 

 latter usually concealing the former. Morphologically, the 

 first generation of down or feathers is known as ncosso- 

 ptiles, and the second and subsequent generations as 

 teleoptiles. In niany species the neossoptiles are entirely 

 suppressed. Some writers distinguish between the neosso- 

 ptiles that precede the down and those that precede tlie 

 leathers, calling the former pre|)lumul8e and the latter 

 prepenna3. In some species the neossoptiles^ are entirely 

 preplumnlse, in others entirely prepennse, whilst in many 

 species they are both prepennie and preplumulse. 



Newton, while noting that adult birds are clothed w"ith 

 down and feathers, regards them as morphologically identical, 

 but the down representing a more primitive type of feather 

 (Newton, Diet, of Birds, p. 2 12). Without going into this 

 matter in detail, what happens in the case of the Eagle-Owl 

 is now pretty clear. The first white down repi"escnts the 

 neossoptiles ; my second and third plumages form together 

 the first generation of the teleoptiles; but since they do not 

 appear simultaneously at first, we have an apparent second 

 plumage consisting solely of the first teleoptile down, and 

 an apparent third plumage, which corresponds with the 

 "juvenile" plumage, consisting of the first teleoptile 

 feathers. 



The Barn-Owl seems to offer a slightly different problem. 

 When hatched it is covered with a short white down, which 

 is succeeded by a long white down followed by true feathers. 

 It differs from the Eagle-Owl in the fact that the first true 

 feathers are the second generation of teleoptiles and bear 

 the long second down at their tips. It follows, therefore, 

 that the long second down of the 13arn-0wls corresponds to 

 the first teleoptile or juvenile plumage, but in the Barn- 

 Owls it is entirely downy, whereas in the Eagle-Owl it is a 

 "downy feather." It is probable, however, that in the 

 Barn-Owl, as in the Eagle-Owl, the first teleoptile down 

 precedes the first teleoptile '^ feathers," but that in the Barn- 

 Owl they are indistinguishable. While on this subject I have 

 had occasion to look at Sparrow-Hawks, having souie downy 



