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University of California Publications in Zoology [Vol. 13 



d. ridge 



Fig. C. Cross-section of hypothetical barb. Ab- 

 breviations: dist. I., distal ledge; 

 d. ridge, dorsal ridge; gr., groove for 

 insertion of distal barbule; i^rox. I., 

 proximal ledge; v. ridge, ventral ridge. 



Ventral Ridge (figs. B and C). A horny keel on 

 the ventral side of the ramus, usually nar- 

 row, though sometimes very highly developed 

 (Strong, 1902; Mascha, 1905). German syno- 

 dffg nym: Hornleiste (Mascha, 1904). 



Ledge (fig. C). Longitudinal grooved ledges on 



the lateral sides of some rami, into which 



Fi«- C the barbules fit and which tend to hold them 



in place. Indefinitely called "ridges" or "longitudinal ridges" by Mascha 



(1905). German synonyvi: Gesims (Mascha, 1904). 



Barbule (figs. D, E and F). A branch of a ramus, collectively forming 

 the vanules. Pennaceous barbules are those which are differentiated 

 into a proximal and distal series which interlock by means of booklets, 

 unless the structure has been secondarily simplified. The proximal 

 barbules (fig. D) are those which are borne on the side of the ramus 

 nearest the base of the feather. The distal barbules (fig. E) those 

 which are borne on the side nearest the tip. Downy barbules (fig. F) 

 are those which are relatively long and filamentous, with no interlocking 

 device. Synonym: radius, a common alternative; tertiary fibers (Mascha, 

 1905); hook fibers (= distal barbules) and curved fibers (= proximal 

 barbules) (Mascha, 1904). German synonyms: Strahlen (Nitzsch, 1867; 

 Gadow, 1891; Wiedersheim; secundare Strahlen (Studer, 1878); Fieder- 

 chen (Ahlborn, 1896); tertiare Fasem (Mascha, 1904); Hakenfasern 

 (= distal barbules) and Bogenfasern (= proximal barbules) (Mascha, 

 1904). 



,, d. cil. 



■"• ^- pen. 



Fig. D. Diagrammatic distal barbule. Abbreviations: &., base; d. cil., dorsal 

 cilia; fl., flange; Ji., booklets; n., nucleus; pen., pennulum; v. oil.. 

 ventral cilia; v. t., ventral teeth. 



Fig. E. Diagrammatic proximal barbule. Abbreviations: 6., base; d. sp., 

 dorsal spines; fl., flange; n., nucleus; pe7i., pennulum; v. t., ven- 

 tral teeth. 



