1916] Chandler: Structure of Feathers 321 



specialized ones, except in Leptoptilus, where there are only 2, and 

 these close together. 



(3) Proximal barbules with large bases, inconspicuous ventral 

 teeth, a short but broad and tapering pennulum, and no ventral 

 cilia developed on outer vane. 



(4) Ventral edge of outer rami of primaries serrate in Ibididae 

 and Plataleidae, but smooth in Ciconiidae. 



(5) Body feathers with barbules as in remiges, but more elongate 

 and slender; never any flexules. 



(6) Down barbules in Ciconiidae long, slender, and filamentous, 

 with small inconspicuous prongs or none at all ; in Ibididae short, 

 stout and heavy, longitudinally ribbed, and with well-developed 

 prongs at the nodes. 



III. Suborder Aedeae 

 PI. 20, Figs. 20-22 



As stated above, the typical Ardeae are readily distinguishable 

 from the Ciconiae, but Balaeniceps and Scopus combine the char- 

 acters of both groups in such a way that the characterization of 

 either is very difficult without allowing for these exceptions. 

 Unfortunately I have not been able to obtain feathers of either of 

 these genera for study, in order to find out whether their feather 

 structure adheres to the typical ardean type or approaches that of 

 the Ciconiae. Having no data concerning either of these two out- 

 lying forms, nor of Cochlearius, the present section deals only with 

 the Ardeidae, including the herons, egrets and bitterns. Their 

 general epiphy ological characteristics are as follows : ( 1 ) plumules 

 confined to the apteria, (2) powder down present, (3) aftershaft 

 present, and (4) lores naked. 



a) Ardea herodias 



(1) Remex 



Shaft and rami very similar to those of Ciconiae, the shaft, if 

 anything, slightly deeper than wide, with V-shaped ventral groove, 

 and fine striations on side. Rami not considerably deepened, even on 

 outer vane, the pith not more than a single layer in thickness and 

 the ventral edge not serrate or furnished with villi. Distal vanule 

 with about 30 barbules per millimeter, proximal vanule with about 

 18 per millimeter. 



Inner vane. — Distal harhules (pi. 20, fig. 20a) with small base, 

 about 0.26 by 0.04 mm. with relatively very large, leaf-like ventral 

 teeth so shaped and arranged as to form a single, large, blunt. 



