582 
BULLETIN OF THE BUREAU OF FISHERIES 
§ 
Figure 8. — Diagrammatic sketches of gill filaments; a, A principal filament; 6, cross 
section of a principal filament, through branchial expansion; c, ctenidial or 
branchial axis with principal and ordinary filaments, etc.; d, cross section, 
between branchial expansion and interlamellar septum, of a principal filament 
and adjacent ordinary filaments; e, distal portion of an ordinary filament, spatu- 
late tip drawn carefully from specimen; /, an ordinary filament with a contracted 
spur and with frontal cilia; g, an ordinary filament with connective spurs 
expanded and in various positions to show power of movement. Af., afferent 
branchial vessel; Br. A., branchial artery; Br. Ex., branchial expansion; Br.N., 
branchial nerve; Br. V., branchial vein; Ch., chitinous supporting structure; 
Con., connective spurs; Ct. Ax., ctenidial axis; Ef., efferent branchial vessel; 
I. S., interlamellar septum; Ord., ordinary filament; Pr., principal filament; 
Spa., spatulate tip of filament 
