252 University of California Publications in Zoology (Vor. 138 
Fig. C. Cross-section of hypothetical barb. Ab- 
breviations: dist. 1., distal ledge; 
d. ridge, dorsal ridge; gr., groove for 
Sf ee r. insertion of distal barbule; prox. L., 
OD ieee dist. l. proximal ledge; v. ridge, ventral ridge. 
seeecese pith. Verran River (figs. B and C). A horny keel on 
etna: prox. | ENTRAL RipeE (figs. B an - orny kee 
the ventral side of the ramus, usually nar- 
row, though sometimes very highly developed 
(Strong, 1902; Mascha, 1905). German syno- 
nym: Hornleiste (Mascha, 1904). 
LrepGE (fig. C). Longitudinal grooved ledges on 
the lateral sides of some rami, into which 
Fie. C the barbules fit and which tend to hold them 
in place. Indefinitely called “ridges” or “longitudinal ridges’ by Mascha 
(1905). German synonym: 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 hooklets, 
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 Fasern (Mascha, 1904); Hakenfasern 
(= distal barbules) and Bogenfasern (= proximal barbules) (Mascha, 
1904). 
---- v. ridge. 
5 SSS 
Fig. D. Diagrammatic distal barbule. Abbreviations: b., base; d. cil., dorsal 
cilia; 7l., flange; h., hooklets; n., nucleus; pen., pennulum; v. cil., 
ventral cilia: v. t., ventral teeth. 
Fig. E. Diagrammatic proximal barbule. Abbreviations: b., base; d. sp., 
dorsal spines; 7l., flange; n., nucleus; pen., pennulum; v. t., ven- 
tral teeth. 
