16C) ME, W, P. PTCEAFT 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 Carinatm, 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 A-pteryx 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 Palceognathe there is but one form of teleoptile, corresponding to the 

 contour-feathers of the INeopiatlue, semiplumulse, pluraulse, filoplumulae, and powder- 

 down are all absent. Rictal bristles, such as occur in Ajjteryx, and eye-lashes, such 

 as are found in all other Palceognatlm save A^teryx, are modifications of contour- 

 feathers. 



Meijere claims to have discovered filoplumae in Struthio, Rhea, and Casuarius, and 

 gives figures of each. I cannot, however, confirm this. I have found degenerate 

 feathers in the wing of Casuarius similar to that he figures from the neck of 

 C. paimanus : 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 Palceognathoe. 



In Casuarius the teleoptiles are, on the lower region of the back, of great length, 

 and relatively larger than in Bromceus. 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 Neognathoe. 



The Casuariidm 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 Dromceidce differs conspicuously from that of the Casuariidm 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 Neognathce. In a feather 

 taken from the middle of the ■pteryla spinalis the radii are of great length, and give 



