Fig, 367. The ctenidia of the Lamellibranchiata. A and B, Mytilus C, 

 Anodonta. A, Vertical transverse section through ctenidium of one side. 

 a.v. afferent vein; a.l. ascending, d.L descending limb of filament; cil.d. 

 ciliated discs; e.v. efferent vein; F. foot; U.S. interlamellar space; il.j. inter- 

 lamellar concrescence; ma. mantle; muc. mucus travelling ventrally (in direc- 

 tion of arrows) and jhuc' collected in the food groove; pl.c. plicate canals; 

 r.v. renal veins. B, Horizontal section through two adjacent filaments, bl.c. 

 blood cells ; ch. chitinous rods ; cil.j. ciliary junction ; f.cil.,fl.cil., l.cil. frontal, 

 latero-frontal, lateral cilia. The arrows denote the direction of the food 

 current and the path of the food particles it contains. C, Horizontal section 

 through a gill. Lettering as above. 



