1916] Chandler: Structure of Feathers 327 



with any other Ciconiae, and in the third they are intermediate 

 between the Ciconiae and the Anseres. 



5. Order ANSERIFORMES 



PI. 21, Figs. 28-31 



Comprising the two suborders Anseres and Palamedeae, this order 



is characterized by the uniform distribution of plumules, and 



the absence or rudimentary condition of the aftershaft. The Pala- 



medeae are further characterized by the total absence of apteria, 



a condition found elsewhere only in the Sphenisciformes among 



carinate birds. Since in the finer structure of their feathers the 



^ two suborders have little in common, it will be more advantageous 



to take them up separately. 



I. Suborder Anseres 

 PI. 21, Fig. 28-30 



a) Anas platyrhynchos 



(1) Remex 



Calamus unusually long, being considerably over one-third length 

 of quill in primaries. This elongation is a very constant and char- 

 acteristic feature. Shaft about as broad as deep, with broad, shal- 

 low ventral groove. Rami with rather broad attachment to shaft, 

 especially on outer vane, and differing from all other birds except 

 a few gallinaceous species, in the enormous development of ventral 

 ridge into a broad, thin, filmlike expansion on the basal one-third 

 to two-thirds of the barb, reaching over and adhering to the 

 adjacent ramus in front of it, producing a very conspicuous 

 macroscopic effect on lower side of feather, where the portion of 

 feather plate involved has a shiny, glazed appearance. Plate 21, 

 figure 28a, represents proximal portion of barb from inner vane 

 of a primary, showing expanded ventral edge with filmy expanded 

 ventral ridge ending abruptly. On outer vane, rami further char- 

 acterized by dense villi (pi. 21, fig. 28h). Distal and proximal 

 vanules with barbules not as different in size as in Ciconiae but 

 distals outnumbering proximals nearly as much as in latter group ; 

 about 42 distals and 23 proximals per millimeter on a barb from 

 inner vane of primary. 



Inner va7ie. — Distal harhules (pi. 21, fig. 28c) relatively large 

 for size of feather, base about 0.27 by 0.042 mm., extremely thin 

 and filmy, pigment usually absent below line of nuclei, although this 

 area is wider than usual ; ventral teeth lobate but not blunt or 

 truncate at end, being drawn out more or less into slender points. 

 Hooklets exceedingly slender and delicate, with their hooked tips 

 somewhat enlarged, usually 6 or 7 of them, progressively and 

 regularly becoming longer; ventral cilia long, slender, and not 



