166 MR. W. P. PYCRAFT ON THE MORPHOLOGY AND 
The fate of the prepenna which remains attached to the young definitive feather can 
be conjectured with probable certainty. It is shed or rubbed off as in Carinate, The 
definitive rhachis with its rami appears to be carried for a short while longer, and then 
to break off from the calamus by which it was supported. The fracture takes place at 
the upper umbilicus, and leaves only the calamus. This appears to go on growing and 
thickening its walls, so that in course of a short time it becomes the solid, elastic spine 
so familiar in, and peculiar to, the Cassowaries. 
In the wing of the adult Apteryx we have an almost similar series of wing-spines. 
These differ, apparently, from those of Casuarius only in that they have retained the 
rhachis and its rami, and in that the calamus is yet hollow. In one point, however, 
they differ markedly, inasmuch as they have what is possibly a vestigial aftershaft. 
This can be readily seen as an elongation of the central lip of the calamus, the sides 
of which bear numerous rami. 
The Teleoptiles. 
In the Palwognathe there is but one form of teleoptile, corresponding to the 
contour-feathers of the Neognathe, semiplumule, plumule, filoplumule, and powder- 
down are all absent. Rictal bristles, such as occur in Apteryx, and eye-lashes, such 
as are found in all other Palwognathw save Apteryx, are modifications of contour- 
feathers. 
Meijere claims to have discovered filoplume in Struthio, Rhea, and Casuarius, and 
gives figures of each. I cannot, however, confirm this. I have found degenerate 
feathers in the wing of Caswarius similar to that he figures from the neck of 
C. papuanus : these, however, I regard as degenerate contour-feathers. I failed to find 
anything in Rhea corresponding to his figure; Struthio I have not had an opportunity 
of examining. He failed to find them in other Palwognathe. 
In Casuarius the teleoptiles are, on the lower region of the back, of great length, 
and relatively larger than in Dromeus. Only the rami of the lower part of the feather, 
from wherever taken, bear radii, and these appear to be entirely destitute of fila. The 
rami throughout the greater part of the length of the feathers are long and hair-like, 
reminding one of egret-plumes. 
The hyporhachis is nearly or quite as long as the main shaft, and does not differ 
therefrom structurally, as in Neognathe. 
The Casuariide are remarkable for the enormous spines, 5 in number, which are 
borne by the wing. ‘These are degenerate remiges, and are dealt with above. 
The plumage of the Dromwide differs conspicuously from that of the Casuariide by 
its greater softness of texture. In the latter it is harsh and coarse. 
The rami are closely set, as in typical contour-feathers of Neognathe. In a feather 
taken from the middle of the pteryla spinalis the radii are of great length, and give 
