292 University of California Publications in Zoologij [Vol. 13 



forming compact, well-developed vanes, the result being that the 

 plumage of these birds is much coarser and more bristly than that 

 of emus. 



The feathers have a somewhat different general shape. While 

 in emus they are elongate and narrow with approximately a uniform 

 width throughout, in cassowaries their widest point is a few centi- 

 meters above the umbilicus, thence more or less gradually tapering 

 to the tip. The aftershaft is as highly developed as in emus, and 

 as with the latter resembles the main feather plate in structure as 

 well as size. The calamus is exceedingly short, shorter in Casuarius 

 uniappendiculatus than in C. papuanus; in fact, it is so short in the 

 former that the division into shaft and aftershaft occurs under 

 the surface of the skin, the feather thus appearing completely 

 double. The barbs are moderately developed, not sword-shaped, 

 and spaced about 7 or 8 per centimeter, increasing to 16 per centi- 

 meter at the base; the barbules (pi. 14, figs. Sa, 3&) are of about 

 the same length as in Dromaeus (1 to 1.8 mm.) but entirely lack 

 the prongs at the nodes, the latter being indistinguishable, and the 

 pennula simple threads. The naked terminal portion of the 

 feather, which sometimes constitutes three-fourths of the entire 

 feather, and reaches a length of over 20 cm., sometimes has the stiff, 

 bristle-like naked barbs present in decreasing numbers all the way to 

 the tip, where there are only two or three per centimeter on each side, 

 while in other cases, especially in shorter feathers, the naked shaft 

 is produced as a very coarse, stiff bristle. 



c) Relationships 



While agreeing with the ostriches and rheas in characters 

 common to all the Ratitae, the cassowaries and emus differ from 

 either of the former types far more than they differ from each other. 

 The present group, with the Apterygiformes, on the one hand forms 

 a subdivision of the Ratitae comparable with the Struthioniformes 

 and Rheiformes on the other, though the latter are more nearly 

 related to each other than are the former. The enormous after- 

 shaft, the few reduced remiges, the coarse texture of the plumage, 

 and the form of the barbules, are all striking points of difference 

 from the ostriches and rheas, while in all except the aftershaft 

 they agree more closely Math the Apterygiformes in these characters. 

 Although in their feather structure there is no positive evidence 

 of their being primitively rather than secondarily flightless, there 



