7 56 
Letters , Extracts , and Notes. [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 neosso- 
ptiles, and the second and subsequent generations as 
teleoptiles. In many species the neossoptiles are entirely 
suppressed. Some writers distinguish between the neosso¬ 
ptiles that precede the down and those that precede the 
feathers, calling the former preplumulse and the latter 
prepennse. # In some species the neossoptiles are entirely 
preplumulse, in others entirely prepennye, whilst in many 
species they are both prepennye and preplumulse. 
Newton, while noting that adult birds are clothed with 
down and feathers, regards them as morphologically identical, 
but the down representing a more primitive type of feather 
(Newton, Diet, of Birds, p. 242). Without going into this 
matter in detail, what happens in the case of the Eagle-Owl 
is now pretty clear. The first white down represents 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 dow n, which 
is succeeded by a long w hite 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 dow r n at their tips. It follows, therefore, 
that the long second down of the Barn-Owls corresponds to 
the first teleoptile or juvenile plumage, but in the Barn- 
Owds it is entirely downy, whereas in the Eagle-Owl it is a 
et 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 some downy 
