8 W. P. PYCRAFT. 
neossoptiles represent distinct feather generations, and that therefore the pre-penne, as 
I have elsewhere (11) called those neossoptiles preceding contour feathers, are not, as 
some apparently hold, a part of—‘‘agents in advance” of—the contour feathers which 
succeed them. Consequently, the fact that the bulk of the rami of the pre-penne in 
Pygoscelis adeliz are directly attached to the tips of the rami of the after-shaft of the 
succeeding teleoptile is a somewhat remarkable fact, especially since in all other 
instances yet known the nestling-down, when attached to contour feathers, is attached 
to the rami of the main shaft. In the case now under 
discussion the rami of the pre-penna, which are borne by 
the main axis of the contour feather, are few in number 
and take no appreciable part in the formation of the pre- 
penna as a whole, which is composed of rami connected 
by means of the long ribbon-shaped stalk with the rami of 
the aftershaft, and forming the large tuft of woolly down 
such as is seen in Fig. 8. The significance of this relation 
to the aftershaft must be referred to again later. 
Microscopically the rami of these “ pre-penne” are 
of considerable length, and have short, ribbon-shaped 
spirally-twisted radii which bear only about four pairs 
of minute fila. The spiral twist acts as a kind of felting 
arrangement, whereby the downy covering is “ knitted,” as 
it were, into an almost homogeneous coat. 
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ME on The Nestling Down of the Emperor Penguin. 
iG eee ‘ ‘i : 
WEY This differs not only in colour but also in certain small 
WE structural details from that of the Adélie Penguin. The 
= first down-plumage differs from that which follows, in 
that it is short, barely covers the body, and resembles 
rig. 4.—rHE First (wmossoprytn) anp Silky hair more than feathers; that is to say, when 
ee superficially examined. Under the microscope each down 
MESOPTYLE, feather is found to be made up of several rami, umbelliform 
in arrangement, and of moderate length, each ramus being 
produced into a long filament beyond the radii, which are short. The fila of these radii 
are much larger than in Pygoscelis. This first down-plumage is rapidly succeeded by 
similar umbelliform tufts of much greater length and volume. The rami are about 
twice as long as those which preceded them, but the radii are only, relatively, slightly 
longer, and bear from eight to ten pairs of fila. This generation of down feathers 
differs from the corresponding generation in Pygoscelis, firstly, in that the radii are 
straight instead of spirally twisted, so that the down is less “felted,” and secondly, 
in that instead of being of a uniform character throughout, the rami of the down 
