1916] Chandler: Structure of Feathers 325 



ishing ventral cilia developed, and on inner vane two closely 

 approximated, blunt, stout, dorsal cilia followed by one or two 

 spinelike ones, the rest of the pennulum elongated, slender, and 

 without barbicels. 



(7) Proximal barbules of inner vane with moderately large 

 base, short inconspicuous ventral teeth, and pennulum very slender 

 and threadlike, shorter than base. 



(8) Proximals of outer vane similar to those of inner vane, 

 never developing ventral cilia. 



(9) Body feathers with pennulum of distals usually rather 

 stout, dorsal cilia not developed, the ventral ones conspicuously 

 short and blunt. 



(10) Ornamental plumes with divided vanes frequently de- 

 veloped. 



(11) Down very long, often over 2 mm., the nodes slightly 

 enlarged, sometimes with minute prongs, pigment when present not 

 collected into conspicuous spots. 



IV. Suborder Phoenicopteei 

 PI. 21, Fig. 32 



The flamingoes, in Knowlton's classification, are grouped as a 

 suborder of the Ciconiiformes, but in their characters they are so 

 perfectly transitional between the Ciconiae, especially the ibises, on 

 the one hand, and the Anseriformes on the other, that, while 

 evidently forming a suborder of their own, the question as to 

 the group with which they are more closely associated has been 

 one of the most debated questions in the classification of birds. 

 Their feather structure, therefore, is of unusual interest, on account 

 of the light which it throws on this relationship. 



As in both the Ciconiae and the Anseriformes, the down is 

 here also uniformly distributed. The aftershaft is present, which is 

 an interesting fact considering that in the Ciconiae it is very 

 variable, while in the Anseriformes it is rudimentary or absent. 

 There are twelve primaries as in some Ciconiae, whereas in 

 Anseriformes there are only eleven. 



a) Phoenicopterus ruher 



(1) Remex 



Shaft of remiges slightly wider than deep, with shallow median 

 groove. Pith of rami more than one cell in thickness ; whole ventral 



