D Gr. 



En. 



Fig. 6. — Diagram of a transverse section 

 of the pharynx and atrium of Amphioxus 

 to show the ciHary mechanisms on the gill, 

 which produce the main current and collect 

 and transport food-particles. (This diagram 

 serves equally well also for Ascidians.) 



Ph. Pharynx, in the walls of which are 

 shown several gill-bars. 



At. Atrium. 



En. Endostyle, the lateral cilia of which 

 pass on mucus and food-particles from the 

 median cilia to the gill- bars. 



D.Gr. Dorsal groove of pharynx. 



l.f.c. Lateral cilia on the gill-bars. 



These produce the main current which 

 passes across the gill from the pharynx to 

 the atrium in the direction indicated by 

 the large arrows which cross the gill-bars 

 about the middle of the figure. (These 

 cilia should have been denoted in the 

 figure by the letters I.e.) 



f.c. Frontal or jDharyngeal cilia. These 

 cilia are the chief collectors and trans- 

 porters of food-particles, which become 

 caught in the mucus passed on to the 

 gill from the endostyle. The captured 

 food -particles are trans^jorted towards and 

 into the dorsal groove, as indicated by the 

 arrows along the inside of the gill- bars. 



