446 



SUB- PHYLUM CEPHALOCHORDA. 



coe 



rrv 



FIGS. 219 and 220. The Nephridia of Amphioxus. After Boveri. 



Both figures are lateral views of the upper region of the pharynx, the 

 body- wall being removed. In the upper figure the atrial 

 chamber is laid completely open by the removal of its outer 



