168 ME. W. P. PTCEAFT ON THE MORPHOLOGY AND 



In the DmornifhidcE the rami and radii are short. The latter, from the middle of 

 the feather to its base, are filiform and divided into a series of numerous short joints, 

 the anterior ends of which are produced into two or three pointed fila. Thus these 

 radii most nearly approach those of Apteryx, but they may be at once distinguished 

 therefrom by the relatively great length of the fila. 



The distal ends of the rami bear no radii. 



The feathers of Dinorms were first described by Dallas [15]. His description is 

 appended below : — 



"The structure of the web is somewhat different from that which occurs in the Emu 

 and the Cassowary. Towards the base of the shaft the barbs spring in groups of four 

 or five together from nearly the same spot, and thus this part of the web assumes a 

 tufted aspect. As we advance towards the apex this arrangement speedily ceases ; the 

 number of barbs springing from the shaft gradually diminislies until each side bears 

 only a single series of these appendages. The barbs consist of slender, flattened fibres, 

 bearing long, silky, and very delicate barbules, without any trace of barbicels, and 

 presenting a distinctly beaded appearance when examined by a simple lens. Under 



the microscope the barbule appears merely divided by faint transverse partitions 



into a series of cells, some of which towards the apex exhibit small tooth-like projections 



representing rudiments of barbicels The barbs nearest the base of tlie feather, 



botli in the main web and accessory plume, are destitute of barbules for some distance 

 from their base; but this distance gradually decreases until the barb is furnished with 

 barbules throughout its whole length." 



As Dallas remarks, these fragments still leave us in ignorance of many points, 

 such as whether the basal rami (barbs) possessed the hair-like tips of the Emu and 

 Cassowary, and whether the apical portion of the feather supported simple rami as 

 in these last. 



SUMMAEY OF PtERYLOLOGICAL CHARACTERS. 



Perhaps the most interesting pterylological result of the present enquiry has been 

 the light thrown upon the history of the remarkable wing-spines or vestigial remiges 

 of Casuarms. The comparison of these with the remiges of the nestling on the one 

 hand, and with the wing of Apferyx on the other, leaves little or no dmibt but that 

 the explanation, or rather interpretation, of the nature of these degenerate feathers is 

 correct. 



The form and disposition of the apteria have been described at greater length than 

 ever before, and some new facts added. The existence of apteria has kmg been known — 

 at least in Struthio and Apteryx; though these facts had not yet found thiir way into 

 the text-books, which still repeat the old error that the feathers of the FcdoeoguathcB 

 weie evenly distributed over the body. 



The form and structure of the nestling-down has been worked out iu considerable 



