CILIARY MECHANISMS ON THE GILL IN AMPHIOXUS. 



21 



If the animal is examined closely by means of a microscope when 

 feeding it is easy to make out a strong current entering at the anterior end 

 of the animal between the buccal tentacles. Thence the current can be 

 followed successively through the buccal cayity. the mouth, the pharynx. 



FOOD-MA' 



DORSAL GROOVE 



Fig. 2. — View of a portion of the body wall and pharynx of a living entire Amphioxus at 

 about the level of the posterior two-thirds of the pharynx.* (Drawn as seen 

 through a microscope, x about 37.) 



D.Gr. Dorsal groove in which becomes collected a mass of food particles embedded 

 ui mucus. 

 Cylindrical mass of mucus with embedded food-particles being transported 

 away from the endostyle towards the dorsal groove, as is indicated by 

 the overlying vertical arrows. 

 The boundary of adjacent myotomes. 



F.M. 



M. 



* It was found the most convenient for this examination to view the animal laid on 

 its right side. Thus in this view the main current passes from the reader's right to the lefti 



