121 [Vol. xl. 
Capt. C. Incram exhibited a series of down-feathers from 
the back of an Hider duckling (Somateria mollissima), and 
made the following remarks :— 
Last summer, upon releasing a fully-developed embryo 
from an abandoned Hider’s egg “(the old bird, having hatched 
off part of the clutch, had made her way to the coast) I 
found that the dead duckling had the usual moist and 
bedraggled appearance. A closer scrutiny, however, showed 
that its covering, clogged and matted though it was, looked 
much more like wet hair of coarse texture than the moist 
fluffy down-feathers I had expected to find. After carefully 
drying this specimen I was surprised to discover that each 
down-feather was separately and completely encased in a 
protective sheath, evidently analogous in structure to the 
brittle covering that surrounds the adult feathers during 
growth. When so encased each down-feather, although 
frequently composed of twenty or more burbs, is packed 
into a remarkably small space—in fact, the whole of the 
sheath-encased feather is then no thicker than a medium-sized 
horse-hair. 
This sheath is very friable and, when dry, crumbles away 
at the slightest touch—hence its complete disappearance a 
few hours after hatching. This explains the almost perfect 
velvet-like condition of the downy covering of newly-hatched 
chicks within a few hours of batching. 
In the down-feather marked No. 1 in the exhibit, the 
sheath is unbroken and the barbs are completely encased. 
In Nos. 2, 3, and 4, the sheath has been partly removed, 
while in No. 5 it has been entirely rubbed off and the feather 
completely released. 
Mr. G. M. Maruews sent the following communication :— 
““ As Acanthiza clelandi and A. whitei are both preoccupied, 
the bird described by me as A. n. clelandi (ante p. 106) 
can be called A. n. _purtoni, and A. 1. whiter (p. 106) 
A. 1..alberti.” 
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